Year Percent 1980-01-01 1.0590100000000000 1981-01-01 1.2314900000000000 1982-01-01 1.5231299999999999 1983-01-01 2.2410400000000004 1984-01-01 2.7116000000000000 1985-01-01 3.6135200000000000 1986-01-01 3.0097000000000000 1987-01-01 3.0227700000000000 1988-01-01 3.0299300000000000 1989-01-01 2.9799500000000000 1990-01-01 3.5166199999999996 1991-01-01 3.7935800000000004 1992-01-01 4.3972700000000000 1993-01-01 8.8451500000000000 1994-01-01 11.1209999999999990 1995-01-01 11.9323000000000000 1996-01-01 14.4977000000000000 1997-01-01 16.9883000000000000 1998-01-01 21.7555000000000000 1999-01-01 24.8446000000000000 2000-01-01 30.7605000000000000 2001-01-01 32.8790000000000000 2002-01-01 35.7897000000000000 2003-01-01 40.6906000000000000 2004-01-01 38.3567000000000000 2005-01-01 40.3421000000000000 2006-01-01 55.8129000000000000 2007-01-01 65.0767000000000000 2008-01-01 65.3230000000000100 2009-01-01 78.9329000000000000 2010-01-01 77.2057000000000000 2011-01-01 74.5056000000000000 2012-01-01 86.8938000000000000 2013-01-01 86.3148000000000000 2014-01-01 74.6058000000000000 2015-01-01 76.4722000000000000 2016-01-01 66.5700000000000000