Year	Percent
1991-01-01	41.8759994506836
1992-01-01	40.9150009155273
1993-01-01	35.7150001525879
1994-01-01	35.2750015258789
1995-01-01	34.8230018615723
1996-01-01	33.1419982910156
1997-01-01	31.8929996490479
1998-01-01	26.0440006256104
1999-01-01	26.6450004577637
2000-01-01	24.1870002746582
2001-01-01	25.0680007934570
2002-01-01	28.2770004272461
2003-01-01	27.1800003051758
2004-01-01	27.7229995727539
2005-01-01	26.9680004119873
2006-01-01	21.6669998168945
2007-01-01	20.9130001068115
2008-01-01	18.2759990692139
2009-01-01	20.6599998474121
2010-01-01	18.9729995727539
2011-01-01	17.0440006256104
2012-01-01	16.9160003662109
2013-01-01	19.9880008697510
2014-01-01	20.8029994964600
2015-01-01	20.6170005798340
2016-01-01	22.0659999847412
2017-01-01	20.7430000305176