                                                                                1921                                                          
        1937                                                                            
                                                                                                                                                  1947                                         1943  1947                                     1948                                                           1953  1954                    1956  1964       1963        1970                                     1982                                                   1973  1979                                             414                                                                                                                                                   1965                           1979                                                             1950                                             1960                                  1942     18                          1963                                  1976                                                     1986                                            1989                        1990                                              1989                                                                                        1988                                                                                            1989     66                                                  1950                      1961                                                                                                                                        1961                                                                    1991                 800  1000          