Year Number 1960 3349316 1961 3560717 1962 3815085 1963 4088345 1964 4382367 1965 4697467 1966 4994752 1967 5293097 1968 5612723 1969 5953800 1970 6319334 1971 6626792 1972 6910649 1973 7207161 1974 7518187 1975 7844025 1976 8151709 1977 8455525 1978 8772796 1979 9103750 1980 9449544 1981 9838042 1982 10255564 1983 10691381 1984 11146960 1985 11621250 1986 12081698 1987 12545347 1988 13028586 1989 13530218 1990 14053150 1991 14503135 1992 14925862 1993 15360308 1994 15808652 1995 16270732 1996 16747655.999999998 1997 17237879 1998 17711183 1999 18174366 2000 18651191 2001 19229175 2002 19868003 2003 20528831 2004 21213396 2005 21919627 2006 22651235 2007 23408128 2008 24192300 2009 25001389 2010 25839645 2011 26706973 2012 27400782 2013 27903045 2014 28416288 2015 28908251 2016 29377612 2017 29853900 2018 30339219 2019 30836753 2020 31344136 2021 31852051 2022 32346597 2023 32815076