Year Number 1960 44238 1961 44850 1962 45462 1963 46042 1964 46599 1965 47169 1966 47755 1967 48317 1968 48854 1969 49389 1970 49907 1971 50380 1972 50802 1973 51196 1974 51565 1975 51880 1976 52144 1977 52388 1978 52602 1979 52755 1980 52880 1981 53168 1982 53594 1983 53987 1984 54346 1985 54663 1986 54929 1987 55144 1988 55325 1989 55479 1990 55609 1991 55723 1992 55862 1993 56017 1994 56127 1995 56192 1996 56203 1997 56148 1998 56045 1999 55925 2000 55810 2001 55700 2002 55587 2003 55395 2004 55114 2005 54797 2006 54464 2007 54143 2008 53871 2009 53620 2010 53341 2011 53026 2012 52710 2013 52397 2014 52139 2015 51944 2016 51704 2017 51523 2018 51425 2019 51288 2020 51199 2021 51123 2022 51020 2023 50986