Year Number 1960 39000 1961 34000 1962 30000 1963 27000 1964 25000 1965 25000 1966 24500 1967 24000 1968 24000 1969 25000 1970 25300 1971 25000 1972 25000 1973 25000 1974 25000 1975 20000 1976 25000 1977 20000 1978 20000 1979 25000 1980 15525 1981 17899 1982 34963 1983 37298 1984 39099 1985 40534 1986 41176 1987 41228 1988 39830 1989 39405 1990 34938 1991 34508 1992 62355 1993 57687 1994 40703 1995 34385 1996 89116 1997 84394 1998 80294 1999 82076 2000 15493 2001 14375 2002 14122 2003 16097 2004 17777 2005 21212 2006 25475 2007 30767 2008 37546 2009 38895 2010 42613 2011 47055 2012 51707 2013 55575 2014 60724 2015 72198 2016 93242 2017 115252 2018 128779 2019 135951 2020 141816 2021 152514 2022 258613 2023 257811