Year	Percent
1960-01-01	3.1668600000000000
1961-01-01	3.9119500000000000
1962-01-01	4.2990200000000000
1963-01-01	4.1688500000000000
1964-01-01	4.1483900000000000
1965-01-01	3.6395199999999996
1966-01-01	3.6361300000000000
1967-01-01	1.9957300000000000
1968-01-01	3.6439900000000000
1969-01-01	4.3791100000000000
1970-01-01	1.7330299999999998
1971-01-01	1.8983700000000001
1972-01-01	2.8318700000000000
1973-01-01	3.8194100000000000
1974-01-01	4.4371300000000010
1975-01-01	5.5604000000000000
1976-01-01	7.3870900000000000
1977-01-01	8.1797000000000000
1978-01-01	7.6474000000000000
1979-01-01	7.7329399999999990
1980-01-01	7.6515000000000000
1981-01-01	7.6527699999999990
1982-01-01	7.9743100000000010
1983-01-01	8.3683700000000000
1984-01-01	9.4754000000000000
1985-01-01	9.6509700000000000
1986-01-01	10.2578000000000000
1987-01-01	11.4059000000000000
1988-01-01	12.3422000000000000
1989-01-01	12.2828000000000000
1990-01-01	11.8698000000000000
1991-01-01	11.6704000000000000
1992-01-01	12.0035000000000000
1993-01-01	11.5119000000000000
1994-01-01	11.8950000000000000
1995-01-01	12.0840000000000010
1996-01-01	11.6498000000000000
1997-01-01	11.3233000000000000
1998-01-01	11.1576000000000000
1999-01-01	10.9086000000000000
2000-01-01	12.1800000000000000
2001-01-01	12.6205000000000000
2002-01-01	13.2465000000000000
2003-01-01	14.0136000000000000
2004-01-01	14.7999000000000000
2005-01-01	14.2101000000000000
2006-01-01	14.5416000000000000
2007-01-01	15.7013000000000000
2008-01-01	16.3640000000000000
2009-01-01	18.0940000000000000
2010-01-01	20.4040000000000000
2011-01-01	22.2698000000000000
2012-01-01	23.3618000000000000
2013-01-01	25.9538000000000000
2014-01-01	27.9482000000000000
2015-01-01	29.4952000000000000
2016-01-01	30.9815000000000000