Year	Percent
1976-01-01	39.4347
1977-01-01	34.1940
1978-01-01	39.0806
1979-01-01	34.2298
1980-01-01	30.9667
1981-01-01	30.9667
1982-01-01	34.8867
1983-01-01	36.4149
1984-01-01	36.5539
1985-01-01	38.8485
1986-01-01	40.3449
1987-01-01	41.4408
1988-01-01	39.4598
1989-01-01	37.2817
1990-01-01	37.9301
1991-01-01	39.2208
1992-01-01	37.5405
1993-01-01	37.3919
1994-01-01	38.2429
1995-01-01	40.3204
1996-01-01	44.0691
1997-01-01	47.3911
1998-01-01	49.1729
1999-01-01	50.9226
2000-01-01	51.1145
2001-01-01	54.3275
2002-01-01	54.3865
2003-01-01	52.8336
2004-01-01	54.2300
2005-01-01	56.8284
2006-01-01	57.9836
2007-01-01	63.0519
2008-01-01	70.1303
2009-01-01	76.4869
2010-01-01	76.9331
2011-01-01	74.4471
2012-01-01	74.0469
2013-01-01	75.9754
2014-01-01	75.5499
2015-01-01	79.3198
2016-01-01	83.7035