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
12500
12499
12498
12497
12496
12495
12494
12493
12492
12491
12490
12489
12488
12487
12486
12485
12484
12483
12482
12481
12480