Year	Percent
1960-01-01	19.3580
1961-01-01	18.9325
1962-01-01	19.1092
1963-01-01	19.4575
1964-01-01	19.0855
1965-01-01	18.3982
1966-01-01	20.2962
1967-01-01	20.3804
1968-01-01	20.1817
1969-01-01	22.1684
1970-01-01	16.3110
1971-01-01	18.6436
1972-01-01	20.5039
1973-01-01	20.1831
1974-01-01	19.7553
1975-01-01	22.4262
1976-01-01	25.2424
1977-01-01	26.2697
1978-01-01	32.1002
1979-01-01	31.1503
1980-01-01	27.7082
1981-01-01	30.5828
1982-01-01	35.4039
1983-01-01	46.4646
1984-01-01	51.2265
1985-01-01	55.2013
1986-01-01	56.4424
1987-01-01	56.2049
1988-01-01	56.7048
1989-01-01	55.3669
1990-01-01	50.4157
1991-01-01	49.2494
1992-01-01	48.3024
1993-01-01	46.9909
1994-01-01	45.8217
1995-01-01	46.5252
1996-01-01	47.1702
1997-01-01	51.6297
1998-01-01	55.2379
1999-01-01	53.4986
2000-01-01	48.0767
2001-01-01	50.1088
2002-01-01	51.7703
2003-01-01	41.0499
2004-01-01	37.5269
2005-01-01	37.1382
2006-01-01	38.8833
2007-01-01	37.4187
2008-01-01	33.1242
2009-01-01	55.7337
2010-01-01	53.3712
2011-01-01	44.7596
2012-01-01	48.3876
2013-01-01	50.2209
2014-01-01	53.6985
2015-01-01	62.7771
2016-01-01	68.6942