Year Dollars 1992-01-01 18103574 1997-01-01 13649327 2002-01-01 9642720 2003-01-01 7664720 2004-01-01 9629440 2005-01-01 12420101 2006-01-01 15077208 2007-01-01 18968068 2008-01-01 16095633 2009-01-01 16889924 2010-01-01 18339956 2011-01-01 23758697 2012-01-01 17676746 2013-01-01 18995235 2014-01-01 20453587 2015-01-01 18448178 2016-01-01 15218621