Year Number 1971 3177739 1972 3198670 1973 3300153 1974 3358693 1976 3475749 1977 3564473 1978 3711464 1979 3837800 1980 3968300 1981 4148342 1982 4405947 1983 4537790 1984 4638735 1985 4615888 1986 4710616 1987 5009850 1988 5046471 1989 5202508 1990 4848158 1991 5384539 1992 5869297 1993 5919339 1994 5896026 1995 5530502 1996 5413752 1997 5136152 1999 4732947 2000 4857955 2001 4781543 2002 4778851 2003 4889325 2004 4932646 2005 4948198 2006 4969445 2007 5013582 2008 5109630 2009 5094623 2010 5125942 2014 5177276 2016 5321524 2017 5388349 2018 5299765