Year	Percent
1960-01-01	15.1951
1961-01-01	14.8939
1962-01-01	14.7028
1963-01-01	15.3033
1964-01-01	15.3795
1965-01-01	15.8196
1966-01-01	16.5125
1967-01-01	16.4198
1968-01-01	16.4439
1969-01-01	18.0971
1970-01-01	12.6655
1971-01-01	13.6437
1972-01-01	13.9357
1973-01-01	14.8134
1974-01-01	15.1916
1975-01-01	15.3406
1976-01-01	15.8675
1977-01-01	16.9314
1978-01-01	17.7057
1979-01-01	17.5818
1980-01-01	17.1454
1981-01-01	16.9048
1982-01-01	18.7632
1983-01-01	20.9388
1984-01-01	21.8842
1985-01-01	20.7035
1986-01-01	20.6356
1987-01-01	21.8354
1988-01-01	22.9914
1989-01-01	23.5414
1990-01-01	22.7354
1991-01-01	21.7102
1992-01-01	21.9809
1993-01-01	21.6008
1994-01-01	20.4685
1995-01-01	20.5094
1996-01-01	22.4162
1997-01-01	28.1619
1998-01-01	33.6269
1999-01-01	37.2108
2000-01-01	37.8590
2001-01-01	39.8236
2002-01-01	41.7914
2003-01-01	42.6093
2004-01-01	43.3010
2005-01-01	44.9183
2006-01-01	47.7021
2007-01-01	50.7893
2008-01-01	51.3625
2009-01-01	50.2233
2010-01-01	49.1147
2011-01-01	49.0835
2012-01-01	49.7352
2013-01-01	51.3767
2014-01-01	52.0339
2015-01-01	51.6184
2016-01-01	53.0697