Y \ X
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
6660
6659
6658
6657
6656
6655
6654
6653
6652
6651
6650
6649
6648
6647
6646
6645
6644
6643
6642
6641
6640