Year	Percent
1960-01-01	14.8527
1961-01-01	14.6917
1962-01-01	14.2383
1963-01-01	13.8836
1964-01-01	14.6344
1965-01-01	16.3506
1966-01-01	16.7377
1967-01-01	18.3462
1968-01-01	18.4681
1969-01-01	19.1376
1970-01-01	20.4414
1971-01-01	21.1832
1972-01-01	22.3093
1973-01-01	22.2457
1974-01-01	21.0294
1975-01-01	20.6856
1976-01-01	20.2829
1977-01-01	19.3559
1978-01-01	18.8274
1979-01-01	15.5689
1980-01-01	15.0786
1981-01-01	16.8796
1982-01-01	21.1277
1983-01-01	21.9450
1984-01-01	20.6227
1985-01-01	20.0206
1986-01-01	21.7979
1987-01-01	23.1257
1988-01-01	22.5976
1989-01-01	21.5040
1990-01-01	19.7594
1991-01-01	20.6676
1992-01-01	21.6999
1993-01-01	20.1753
1994-01-01	21.9324
1995-01-01	23.4974
1996-01-01	26.3728
1997-01-01	27.3233
1998-01-01	21.3331
1999-01-01	27.3298
2000-01-01	29.1341
2001-01-01	33.2242
2002-01-01	34.6489
2003-01-01	32.6075
2004-01-01	30.4516
2005-01-01	33.4791
2006-01-01	36.9266
2007-01-01	39.1381
2008-01-01	40.0827
2009-01-01	44.2786
2010-01-01	44.5496
2011-01-01	42.0424
2012-01-01	41.9854
2013-01-01	41.9779
2014-01-01	43.3589
2015-01-01	42.8183
2016-01-01	44.3408