| Value | Category | 
|---|---|
| 0000 | Never worked | 
| 1900 | 1900 | 
| 1901 | 1901 | 
| 1902 | 1902 | 
| 1903 | 1903 | 
| 1904 | 1904 | 
| 1905 | 1905 | 
| 1906 | 1906 | 
| 1907 | 1907 | 
| 1908 | 1908 | 
| 1909 | 1909 | 
| 1910 | 1910 | 
| 1911 | 1911 | 
| 1913 | 1913 | 
| 1915 | 1915 | 
| 1919 | 1919 | 
| 1920 | 1920 | 
| 1921 | 1921 | 
| 1922 | 1922 | 
| 1923 | 1923 | 
| 1924 | 1924 | 
| 1925 | 1925 | 
| 1926 | 1926 | 
| 1927 | 1927 | 
| 1928 | 1928 | 
| 1929 | 1929 | 
| 1930 | 1930 | 
| 1931 | 1931 | 
| 1932 | 1932 | 
| 1933 | 1933 | 
| 1934 | 1934 | 
| 1935 | 1935 | 
| 1936 | 1936 | 
| 1937 | 1937 | 
| 1938 | 1938 | 
| 1939 | 1939 | 
| 1940 | 1940 | 
| 1941 | 1941 | 
| 1942 | 1942 | 
| 1943 | 1943 | 
| 1944 | 1944 | 
| 1945 | 1945 | 
| 1946 | 1946 | 
| 1947 | 1947 | 
| 1948 | 1948 | 
| 1949 | 1949 | 
| 1950 | 1950 | 
| 1951 | 1951 | 
| 1952 | 1952 | 
| 1953 | 1953 | 
| 1954 | 1954 | 
| 1955 | 1955 | 
| 1956 | 1956 | 
| 1957 | 1957 | 
| 1958 | 1958 | 
| 1959 | 1959 | 
| 1960 | 1960 | 
| 1961 | 1961 | 
| 1962 | 1962 | 
| 1963 | 1963 | 
| 1964 | 1964 | 
| 1965 | 1965 | 
| 1966 | 1966 | 
| 1967 | 1967 | 
| 1968 | 1968 | 
| 1969 | 1969 | 
| 1970 | 1970 | 
| 1971 | 1971 | 
| 1972 | 1972 | 
| 1973 | 1973 | 
| 1974 | 1974 | 
| 1975 | 1975 | 
| 1976 | 1976 | 
| 1977 | 1977 | 
| 1978 | 1978 | 
| 1979 | 1979 | 
| 1980 | 1980 | 
| 1981 | 1981 | 
| 1982 | 1982 | 
| 1983 | 1983 | 
| 1984 | 1984 | 
| 1985 | 1985 | 
| 1986 | 1986 | 
| 1987 | 1987 | 
| 1988 | 1988 | 
| 1989 | 1989 | 
| 1990 | 1990 | 
| 1991 | 1991 | 
| 1992 | 1992 | 
| 1993 | 1993 | 
| 1994 | 1994 | 
| 1995 | 1995 | 
| 1996 | 1996 | 
| 1997 | 1997 | 
| 1998 | 1998 | 
| 1999 | 1999 | 
| 2000 | 2000 | 
| 2001 | 2001 | 
| 9998 | Unknown | 
| 9999 | NIU (not in universe) |