Year	Percent
1991-01-01	72.3450012207031
1992-01-01	71.9720001220703
1993-01-01	70.5179977416992
1994-01-01	70.5029983520508
1995-01-01	72.7279968261719
1996-01-01	72.7929992675781
1997-01-01	71.8570022583008
1998-01-01	73.6780014038086
1999-01-01	75.5449981689453
2000-01-01	76.8460006713867
2001-01-01	76.6340026855469
2002-01-01	74.7070007324219
2003-01-01	73.7119979858398
2004-01-01	73.3010025024414
2005-01-01	73.8359985351563
2006-01-01	74.4540023803711
2007-01-01	74.9940032958984
2008-01-01	73.8259963989258
2009-01-01	69.2500000000000
2010-01-01	69.2389984130859
2011-01-01	69.0889968872070
2012-01-01	69.8899993896484
2013-01-01	71.0550003051758
2014-01-01	72.5319976806641
2015-01-01	73.9530029296875
2016-01-01	75.4219970703125
2017-01-01	75.1800003051758