Year Dollars 1992-01-01 3550149676 1997-01-01 6542747348 2002-01-01 8906686629 2003-01-01 11065806512 2004-01-01 12454957275 2005-01-01 13197183489 2006-01-01 12792634177 2007-01-01 15662328664 2008-01-01 18665505166 2009-01-01 15756876794 2010-01-01 19362224776 2011-01-01 23442507207 2012-01-01 23819793259 2013-01-01 25139003891 2014-01-01 28190181743 2015-01-01 29415835771 2016-01-01 29558604842