Year	Percent
1960-01-01	32.1574
1961-01-01	31.7357
1962-01-01	33.4318
1963-01-01	33.6900
1964-01-01	29.7904
1965-01-01	26.9188
1966-01-01	26.9577
1967-01-01	30.2044
1968-01-01	33.9343
1969-01-01	32.9730
1970-01-01	32.7031
1971-01-01	30.7551
1972-01-01	30.0976
1973-01-01	26.9663
1974-01-01	25.2290
1975-01-01	20.3494
1976-01-01	19.2746
1977-01-01	18.1634
1978-01-01	18.0542
1979-01-01	18.4455
1980-01-01	18.9913
1981-01-01	17.3950
1982-01-01	15.5537
1983-01-01	17.4408
1984-01-01	18.7243
1985-01-01	20.5596
1986-01-01	21.7915
1987-01-01	22.3556
1988-01-01	25.0088
1989-01-01	28.2735
1990-01-01	31.7724
1991-01-01	33.7042
1992-01-01	36.8081
1993-01-01	37.8456
1994-01-01	36.6527
1995-01-01	36.3787
1996-01-01	35.3981
1997-01-01	34.6896
1998-01-01	34.8437
1999-01-01	37.6398
2000-01-01	39.5512
2001-01-01	39.5890
2002-01-01	42.8721
2003-01-01	49.4997
2004-01-01	52.4188
2005-01-01	58.5612
2006-01-01	76.1990
2007-01-01	84.8165
2008-01-01	88.7348
2009-01-01	97.4753
2010-01-01	91.0413
2011-01-01	84.6098
2012-01-01	82.1191
2013-01-01	76.7543
2014-01-01	76.0728
2015-01-01	73.2040
2016-01-01	66.5647