Year Number 1960 28656 1961 28793 1962 29106 1963 29538 1964 29993 1965 30360 1966 30582 1967 30665 1968 30659 1969 30628 1970 30726 1971 31045 1972 31508 1973 32086 1974 32755 1975 33454 1976 34134 1977 34761 1978 35361 1979 35936 1980 36666 1981 37688 1982 38877 1983 40187 1984 41650 1985 43236 1986 44809 1987 46280 1988 47649 1989 48902 1990 49671 1991 49948 1992 50175 1993 50447 1994 50745 1995 51052 1996 51355 1997 51685 1998 52045 1999 52411 2000 52734 2001 52994 2002 53250 2003 53522 2004 53851 2005 54239 2006 54650 2007 55070 2008 55463 2009 55796 2010 55930 2011 55871 2012 55752 2013 55586 2014 55374 2015 55118 2016 54836 2017 54528 2018 54198 2019 53854 2020 53829 2021 54127 2022 54365 2023 54544