Year	Percent
1960-01-01	54.3836
1961-01-01	58.7242
1962-01-01	60.2826
1963-01-01	71.3430
1964-01-01	61.8010
1965-01-01	60.6835
1966-01-01	66.6650
1967-01-01	60.9275
1968-01-01	61.2070
1969-01-01	71.6191
1970-01-01	72.9174
1971-01-01	84.8293
1972-01-01	82.0205
1973-01-01	51.4563
1974-01-01	39.0954
1975-01-01	38.6132
1976-01-01	34.3107
1977-01-01	32.6674
1978-01-01	29.4158
1979-01-01	25.9367
1980-01-01	24.7295
1981-01-01	23.2847
1982-01-01	21.4008
1983-01-01	23.4704
1984-01-01	37.4001
1985-01-01	46.5535
1986-01-01	54.1146
1987-01-01	54.1035
1988-01-01	50.2808
1989-01-01	54.2873
1990-01-01	55.2489
1991-01-01	41.2724
1992-01-01	34.1600
1993-01-01	35.0434
1994-01-01	34.3706
1995-01-01	34.5615
1996-01-01	38.8929
1997-01-01	45.9896
1998-01-01	53.0592
1999-01-01	68.3831
2000-01-01	81.7024
2001-01-01	73.0442
2002-01-01	60.0409
2003-01-01	56.9771
2004-01-01	58.1828
2005-01-01	67.2505
2006-01-01	72.1496
2007-01-01	71.3591
2008-01-01	72.7073
2009-01-01	71.2115
2010-01-01	66.4528
2011-01-01	61.6492
2012-01-01	61.5403
2013-01-01	66.6484
2014-01-01	70.9500
2015-01-01	71.6175
2016-01-01	69.5885