Year Number 1960 41303 1961 42494 1962 43550 1963 44491 1964 45273 1965 45931 1966 46568 1967 47165 1968 47708 1969 48188 1970 48575 1971 48840 1972 48970 1973 48963 1974 48805 1975 48467 1976 48021 1977 47568 1978 47152 1979 46775 1980 46392 1981 45862 1982 45228 1983 44675 1984 44222 1985 43859 1986 43542 1987 43237 1988 42921 1989 42578 1990 42185 1991 41679 1992 41121 1993 40595 1994 40077 1995 39523 1996 38884 1997 38171 1998 37419 1999 36667 2000 35973 2001 35349 2002 34723 2003 34023 2004 33249 2005 32435 2006 31554 2007 30624 2008 29736 2009 28907 2010 28120 2011 27378 2012 26719 2013 26138 2014 25630 2015 25182 2016 24727 2017 24312 2018 23953 2019 23606 2020 23310 2021 23049 2022 22791 2023 22504