Year	Percent
1980-01-01	30.202200000000000
1981-01-01	31.725400000000000
1982-01-01	38.589800000000000
1983-01-01	42.140700000000000
1984-01-01	42.540700000000000
1985-01-01	41.077500000000000
1986-01-01	40.932900000000000
1987-01-01	39.632400000000000
1988-01-01	36.696700000000000
1989-01-01	36.704400000000000
1990-01-01	33.621000000000000
1991-01-01	31.130000000000000
1992-01-01	29.203300000000000
1993-01-01	29.098200000000000
1994-01-01	29.800300000000000
1995-01-01	28.745500000000000
1996-01-01	29.038500000000000
1997-01-01	29.038500000000000
1998-01-01	31.646700000000000
1999-01-01	24.884900000000000
2000-01-01	27.480000000000000
2001-01-01	23.986600000000000
2002-01-01	25.414500000000000
2003-01-01	25.758900000000000
2004-01-01	24.688200000000000
2005-01-01	23.743300000000000
2006-01-01	26.073000000000000
2007-01-01	27.599500000000000
2008-01-01	28.080800000000000
2009-01-01	29.716200000000000
2010-01-01	30.506400000000000
2011-01-01	30.506300000000000
2012-01-01	29.945999999999998
2013-01-01	30.825800000000000
2014-01-01	31.800000000000000
2015-01-01	31.431900000000000
2016-01-01	30.085400000000000