Year Number 1961 3300 1962 3700 1963 4500 1964 5400 1965 6500 1966 7700 1967 8922 1968 10000 1969 12000 1970 14000 1971 15000 1972 17000 1973 18000 1974 19000 1975 20222 1976 20000 1977 20000 1978 20000 1979 20058 1980 23350 1981 26600 1982 29956 1983 35552 1984 36005 1985 38000 1986 40915 1987 40000 1988 39000 1989 38186 1990 38186 1991 38186 1992 37500 1993 37161 1994 37161 1995 49640 1996 49640 1997 49600 1998 49600 1999 49600 2000 46078 2001 72775