Year	Percent
1960-01-01	1.0035739421039100
1961-01-01	3.4474987204857300
1962-01-01	4.1964996868102600
1963-01-01	2.0185455520782900
1964-01-01	3.2815838516053500
1965-01-01	4.7737795614679600
1966-01-01	3.9096120744314000
1967-01-01	2.4821209437508400
1968-01-01	4.6974209395425500
1969-01-01	5.4466674736593400
1970-01-01	6.3665665645714700
1971-01-01	9.4448426083869600
1972-01-01	7.0710817929150300
1973-01-01	9.1960521723704500
1974-01-01	16.0439987300932000
1975-01-01	24.2072831141663000
1976-01-01	16.5595207920318000
1977-01-01	15.8402728250380000
1978-01-01	8.2631423725205800
1979-01-01	13.4212918958073000
1980-01-01	17.9659245077682000
1981-01-01	11.8766152567118000
1982-01-01	8.5988737987985700
1983-01-01	4.6092961049800000
1984-01-01	4.9607173851200900
1985-01-01	6.0713908842812300
1986-01-01	3.4276171026267400
1987-01-01	4.1489138866069600
1988-01-01	3.9127932832530300
1989-01-01	5.1747311827956900
1990-01-01	7.0287539936102300
1991-01-01	7.5074626865671600
1992-01-01	4.2759961127308100
1993-01-01	2.5163094128611200
1994-01-01	1.9480519480519600
1995-01-01	2.6751592356688000
1996-01-01	2.4565756823821200
1997-01-01	1.8164204407846900
1998-01-01	1.5580399619410100
1999-01-01	1.3467619159152300
2000-01-01	0.7973191587705080
2001-01-01	1.2381061561389100
2002-01-01	1.2342883025705100
2003-01-01	1.3758389261745000
2004-01-01	1.3461326271653900
2005-01-01	2.0359281437125600
2006-01-01	2.3474178403755900
2007-01-01	2.3144286905755100
2008-01-01	3.5969023843488800
2009-01-01	2.1835349660666700
2010-01-01	3.3015689671768300
2011-01-01	4.4632873648900400
2012-01-01	2.8008206226028000
2013-01-01	2.5683297180043600
2014-01-01	1.4719566872514800
2015-01-01	0.0500208420175209
2016-01-01	0.6416131989000950
2017-01-01	2.6908428547772600