YEAR | NUMBER OF PROBLEMS |
---|---|
1927 | 1 |
1930 | 1 |
1931 | 2 |
1932 | 1 |
1933 | 1 |
1934 | 5 |
1935 | 5 |
1936 | 5 |
1937 | 4 |
1938 | 32 |
1939 | 14 |
1940 | 13 |
1941 | 5 |
1942 | 12 |
1943 | 8 |
1944 | 10 |
1945 | 7 |
1946 | 6 |
1947 | 9 |
1948 | 6 |
1949 | 4 |
1950 | 5 |
1951 | 4 |
1952 | 8 |
1953 | 8 |
1954 | 8 |
1955 | 14 |
1956 | 8 |
1957 | 5 |
1958 | 4 |
1959 | 10 |
1960 | 8 |
1961 | 4 |
1962 | 5 |
1963 | 8 |
1964 | 10 |
1965 | 1 |
1966 | 3 |
1967 | 4 |
1968 | 4 |
1969 | 2 |
1970 | 5 |
1971 | 2 |
1972 | 8 |
1973 | 8 |
1974 | 5 |
1975 | 3 |
1976 | 4 |
1977 | 4 |
1978 | 3 |
1979 | 3 |
1980 | 3 |
1981 | 2 |
1982 | 6 |
1983 | 6 |
1984 | 4 |
1985 | 4 |
1986 | 5 |
1987 | 1 |
1988 | 6 |
1989 | 7 |