Year	Percent
1980-01-01	4.5012800000000000
1981-01-01	4.2517800000000000
1982-01-01	4.1076200000000000
1983-01-01	4.1562500000000000
1984-01-01	4.2025600000000000
1985-01-01	4.2189100000000000
1986-01-01	3.9320199999999996
1987-01-01	8.2050300000000000
1988-01-01	12.1673000000000000
1989-01-01	12.3149000000000000
1990-01-01	12.7585000000000000
1991-01-01	9.8533200000000000
1992-01-01	8.9455300000000000
1993-01-01	15.1745000000000000
1994-01-01	13.2106000000000000
1995-01-01	11.7866000000000000
1996-01-01	14.8469000000000000
1997-01-01	21.1788000000000000
1998-01-01	26.4681000000000000
1999-01-01	29.7018000000000000
2000-01-01	27.3282000000000000
2001-01-01	31.7906000000000000
2002-01-01	30.0086000000000000
2003-01-01	35.2040000000000000
2004-01-01	34.1494000000000000
2005-01-01	28.2724000000000000
2006-01-01	22.8865000000000000
2007-01-01	22.9454000000000000
2008-01-01	21.9700000000000000
2009-01-01	27.8999000000000000
2010-01-01	27.5284000000000000
2011-01-01	29.3813000000000000
2012-01-01	27.7093000000000000
2013-01-01	28.0842000000000000
2014-01-01	24.8316000000000000
2015-01-01	23.5485000000000000
2016-01-01	18.5857000000000000