Year Total 1985 34925000 1986 32335000 1987 28995000 1988 26389000 1989 25086000 1990 22887000 1991 19873000 1992 17104000 1993 15638000 1994 14824000 1995 14824000 1996 14987000 1997 15209000 1998 14635000 1999 14752000 2000 14566000 2001 14905000 2002 15312000 2003 15801000 2004 16534000 2005 16697000 2006 16860000 2007 16860000 2008 17104000 2009 17348000 2010 16664000 2011 16860000 2012 16697000 2013 17348000 2014 16371000 2015 16127000 2016 16000000