Year Dollars 1997-01-01 5098193 2004-01-01 2223560 2007-01-01 25629725 2010-01-01 21045153 2011-01-01 10141670 2012-01-01 13632927 2013-01-01 8351965 2015-01-01 56647665 2016-01-01 30985320