Year Number 1960 14693 1961 15194 1962 15685 1963 16191 1964 16733 1965 17289 1966 17960 1967 18627 1968 19285 1969 20232 1970 21879 1971 23541 1972 24702 1973 25345 1974 25842 1975 26089 1976 26279 1977 26530 1978 26654 1979 26635 1980 26676 1981 26875 1982 27112 1983 27289 1984 27399 1985 27399 1986 27375 1987 27405 1988 27426 1989 27441 1990 27567 1991 27807 1992 28089 1993 28443 1994 28866 1995 29197 1996 29451 1997 29854 1998 30345 1999 30804 2000 31250 2001 31631 2002 31907 2003 32047 2004 32082 2005 32043 2006 31864 2007 31645 2008 31492 2009 31342 2010 31330 2011 31476 2012 31647 2013 31829 2014 31972 2015 31724 2016 31375 2017 31017 2018 30667 2019 30356 2020 30019 2021 29585 2022 29090 2023 28587