Year Number 1970 9703748 1971 10006069 1972 10672379 1973 11173497 1974 11636058 1975 12109564 1976 12550573 1977 12823035 1978 13007016 1979 13332113 1980 13813177 1981 14270007 1982 14734175 1983 15171837 1984 15492554 1985 15668802 1986 15937002 1987 16102934 1988 16468960 1989 17036002 1990 17203606 1991 17442876 1992 17682912 1993 18032264 1994 18305802 1995 18574086 1996 18841872 1997 19126866 1998 19307868 1999 19583034 2000 19720780 2001 19933150 2002 19990416 2003 20692268 2004 21341016 2005 21545788 2006 21766718 2007 22212462 2008 22367312 2009 22716970 2010 23118536 2011 23460684 2012 23759800 2013 24673040 2014 25018260 2015 25496502 2016 26151696 2017 26101730 2018 26240260 2019 26840638 2020 27287818 2021 27731760 2022 27831452