Year	Percent
1970-01-01	95.59580000000000
1971-01-01	83.83530000000000
1972-01-01	79.97600000000000
1973-01-01	71.28030000000000
1974-01-01	56.13520000000000
1975-01-01	41.95360000000000
1976-01-01	31.28840000000000
1977-01-01	27.05120000000000
1978-01-01	25.48340000000000
1979-01-01	24.42550000000000
1980-01-01	22.60030000000000
1981-01-01	23.95810000000000
1982-01-01	22.84640000000000
1983-01-01	21.79170000000000
1984-01-01	20.13640000000000
1985-01-01	21.12270000000000
1986-01-01	25.96100000000000
1987-01-01	29.25030000000000
1988-01-01	31.48600000000000
1989-01-01	33.83160000000000
1990-01-01	36.17500000000000
1991-01-01	34.44120000000000
1992-01-01	36.33980000000000
1993-01-01	43.39210000000000
1994-01-01	47.07210000000000
1995-01-01	46.46880000000000
1996-01-01	47.12100000000000
1997-01-01	50.82380000000000
1998-01-01	52.68480000000000
1999-01-01	55.34850000000000
2000-01-01	58.05550000000000
2001-01-01	62.42690000000000
2002-01-01	60.91630000000000
2003-01-01	57.24720000000000
2004-01-01	59.70890000000000
2005-01-01	55.10190000000000
2006-01-01	61.04560000000000
2007-01-01	63.54660000000000
2008-01-01	67.02940000000000
2009-01-01	76.51170000000000
2010-01-01	82.93799999999999
2011-01-01	84.64350000000000
2012-01-01	83.13530000000000
2013-01-01	76.56220000000000
2014-01-01	67.01290000000000
2015-01-01	58.11430000000000
2016-01-01	54.05950000000000