Year	Percent
1960-01-01	14.5540
1961-01-01	14.1296
1962-01-01	13.3457
1963-01-01	13.6726
1964-01-01	14.8763
1965-01-01	15.7286
1966-01-01	15.6063
1967-01-01	16.0299
1968-01-01	16.7230
1969-01-01	17.9373
1970-01-01	17.5351
1971-01-01	18.1231
1972-01-01	20.3232
1973-01-01	20.7228
1974-01-01	17.1565
1975-01-01	23.1168
1976-01-01	27.9169
1977-01-01	30.9832
1978-01-01	34.3269
1979-01-01	30.8165
1980-01-01	28.0966
1981-01-01	29.0789
1982-01-01	30.8324
1983-01-01	35.6086
1984-01-01	29.8861
1985-01-01	30.0099
1986-01-01	32.6940
1987-01-01	28.9129
1988-01-01	26.8384
1989-01-01	20.9101
1990-01-01	21.4339
1991-01-01	25.1294
1992-01-01	23.9345
1993-01-01	21.9751
1994-01-01	20.3616
1995-01-01	18.9257
1996-01-01	12.5753
1997-01-01	13.6883
1998-01-01	15.2869
1999-01-01	14.9964
2000-01-01	13.6052
2001-01-01	14.7309
2002-01-01	13.6036
2003-01-01	14.9930
2004-01-01	14.4612
2005-01-01	15.5066
2006-01-01	20.7853
2007-01-01	27.2992
2008-01-01	22.7630
2009-01-01	27.3421
2010-01-01	24.6798
2011-01-01	26.1446
2012-01-01	31.9890
2013-01-01	37.7504
2014-01-01	48.2940
2015-01-01	46.5258