1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 159 468 926 972 1,992 2,004 2,492 3,146 3,622 5,146                   1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 5,738 6,046 6,678 7,007 7,738 8,490 10,480 9,420 11,139 12,207                   1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 12,636 14,128 14,617 16,000 16,317 16,743 17,335 21,206 23,798 22,185                   1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 22,654 21,700 22,852 23,072 23,770 23,721 21,260 19,286 17,393 18,513                   1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 18,316 18,415 18,038 18,522 19,201 18,584 15,695 14,618 14,192 13,984                   1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 14,523 13,082 13,515 16,233 17,954 18,874 18,241 16,764 17,575 18,556                   2007 2008                 19,782 22,164