Year Dollars 1992-01-01 9466349214 1997-01-01 14986247166 2002-01-01 15296924059 2003-01-01 17306014502 2004-01-01 20380101351 2005-01-01 20657293040 2006-01-01 22515927701 2007-01-01 23957688465 2008-01-01 26941989505 2009-01-01 22486519362 2010-01-01 25122688312 2011-01-01 26424934987 2012-01-01 24216839097 2013-01-01 25267918443 2014-01-01 25697266752 2015-01-01 23789258785 2016-01-01 24368142012