Year Number 1972 4238218.5 1973 4417774 1974 4562628.5 1975 4640724 1976 4766079.5 1977 4960400.5 1978 5082023.5 1979 5110933 1980 5123158 1981 5180996 1982 5225479 1983 5358112 1984 5499427.5 1985 5720237 1986 5968253.5 1987 6227745.5 1988 6445563.5 1989 6613110 1990 6866002 1991 7077510.5 1992 7237791.5 1993 7412221.5 1994 7595150.5 1995 7801708 1996 8128095.5 1997 8405722 1998 8751139 1999 9073079 2000 9349664 2001 9408018 2002 9997552 2003 10456864 2004 10667141 2005 11069757 2006 11077195 2007 11607323 2008 12122278 2009 12478918 2010 12827952 2011 13165694 2012 13245957 2013 13361546 2014 13626080 2015 13933220 2016 14390935 2017 14796765 2018 15448047 2019 16168278 2020 16414487 2021 17240306 2022 17620066