Year Number 1960 55000 1961 53000 1962 51000 1963 50000 1964 47000 1965 47000 1966 40000 1967 34000 1968 33000 1969 30000 1970 31500 1971 29000 1972 29000 1973 20000 1974 11100 1975 16788 1976 17000 1977 17000 1978 17000 1979 32000 1980 33000 1981 35000 1982 21000 1983 35000 1984 36400 1985 36600 1986 35900 1987 22000 1988 23117 1989 25531 1990 25911 1991 24071 1992 24292 1993 24908 1994 19497 1995 31691 1996 36060 1997 36060 1998 15501 1999 16747 2000 18821 2001 12252 2002 12560 2003 12583 2004 13522 2005 15277 2006 16811 2007 17578 2008 17025 2009 15536 2010 17891 2011 22396 2012 22023 2013 25617 2014 29170 2015 35302 2016 42158 2017 42158 2018 42158 2019 61662 2020 64973 2021 74063 2022 150713 2023 167831