Year Total 1970 9944000 1971 12418000 1972 14831000 1973 16667000 1974 17494000 1975 15920000 1976 16766000 1977 17006000 1978 18186000 1979 18243000 1980 16670000 1981 17229000 1982 12226000 1983 13006000 1984 13600000 1985 12342000 1986 10618000 1987 12701000 1988 11820000 1989 11410000 1990 11540000 1991 13240000 1992 13430000 1993 13365000 1994 14011000 1995 14458000 1996 15657000 1997 15391000 1998 15039000 1999 16063000 2000 15192000 2001 15337000 2002 15297000 2003 15923000 2004 14735000 2005 14227000 2006 14054000 2007 12874000 2008 11726000 2009 10962000 2010 9566600 2011 9000300 2012 8136800 2013 7399500 2014 6951200 2015 6471000 2016 5953800