Year	Percent
1960-01-01	15.4091000000000000
1961-01-01	14.6326000000000000
1962-01-01	14.2150000000000000
1963-01-01	14.0834000000000000
1964-01-01	14.1116000000000000
1965-01-01	16.0625000000000000
1966-01-01	18.8443000000000000
1967-01-01	20.6016000000000000
1968-01-01	21.6819000000000000
1969-01-01	21.7273000000000000
1970-01-01	27.0584000000000000
1971-01-01	21.9274000000000000
1972-01-01	18.1305000000000000
1973-01-01	16.3738000000000000
1974-01-01	17.0057000000000000
1975-01-01	18.1366000000000000
1976-01-01	17.7686000000000000
1977-01-01	17.0078000000000000
1978-01-01	20.0227000000000000
1979-01-01	28.7722000000000000
1980-01-01	31.5089000000000000
1981-01-01	36.0512000000000000
1982-01-01	38.7581000000000000
1983-01-01	29.1125000000000000
1984-01-01	14.6499000000000000
1985-01-01	8.8750000000000000
1986-01-01	7.9079900000000000
1987-01-01	6.0742199999999995
1988-01-01	6.0272900000000000
1989-01-01	2.6273500000000000
1990-01-01	5.5335600000000000
1991-01-01	3.7425300000000004
1992-01-01	8.0986800000000000
1993-01-01	10.8812000000000000
1994-01-01	13.7227000000000000
1995-01-01	14.8094000000000000
1996-01-01	13.5312000000000000
1997-01-01	13.7223000000000000
1998-01-01	19.8071000000000000
1999-01-01	19.8441000000000000
2000-01-01	22.1207000000000000
2001-01-01	17.7660000000000000
2002-01-01	14.1639000000000000
2003-01-01	15.8454000000000000
2004-01-01	17.5942000000000000
2005-01-01	19.9803000000000000
2006-01-01	23.3415000000000000
2007-01-01	26.1074000000000000
2008-01-01	27.3891000000000000
2009-01-01	26.3617000000000000
2010-01-01	23.6262000000000000
2011-01-01	22.2248000000000000
2012-01-01	23.7948000000000000
2013-01-01	26.9959000000000000
2014-01-01	28.6010000000000000
2015-01-01	30.8180000000000000
2016-01-01	34.1453000000000000