Year Percent 2008-01-01 3.600000000000000 2009-01-01 4.500000000000000 2010-01-01 5.821720000000000 2011-01-01 9.986239999999999 2012-01-01 18.374900000000000 2013-01-01 38.556999999999995 2014-01-01 44.972100000000000 2015-01-01 47.747800000000000 2016-01-01 48.675800000000000