Year Percent 1980-01-01 0.3209250000000000 1981-01-01 0.3912410000000000 1982-01-01 0.5276420000000000 1983-01-01 0.8691070000000000 1984-01-01 1.2009400000000000 1985-01-01 1.7624000000000000 1986-01-01 2.4989300000000000 1987-01-01 3.0661200000000000 1988-01-01 3.4070400000000003 1989-01-01 4.0343500000000000 1990-01-01 3.8277900000000002 1991-01-01 3.8523300000000003 1992-01-01 3.9745600000000000 1993-01-01 5.2158300000000000 1994-01-01 6.9927100000000010 1995-01-01 8.3667600000000010 1996-01-01 11.3051000000000000 1997-01-01 14.9205000000000000 1998-01-01 18.6943000000000000 1999-01-01 23.6192000000000000 2000-01-01 34.3403000000000000 2001-01-01 38.3422000000000000 2002-01-01 46.6406000000000000 2003-01-01 49.8529000000000000 2004-01-01 53.4359000000000000 2005-01-01 51.3213000000000000 2006-01-01 60.3276000000000000 2007-01-01 60.6860000000000100 2008-01-01 53.8150000000000000 2009-01-01 58.9372000000000000 2010-01-01 54.9481000000000000 2011-01-01 50.5592000000000000 2012-01-01 54.7778000000000000 2013-01-01 51.3880000000000050 2014-01-01 46.5319000000000000 2015-01-01 48.5248000000000000 2016-01-01 46.7409000000000000