Year	Percent of Total
1960-01-01	4.52149333215589
1961-01-01	4.36151542488730
1962-01-01	4.21017276734155
1963-01-01	4.06665899191509
1964-01-01	3.92942696018121
1965-01-01	3.79954581242730
1966-01-01	3.77241857979877
1967-01-01	3.74422482728095
1968-01-01	3.71826490241641
1969-01-01	3.69802033046669
1970-01-01	3.68457464650118
1971-01-01	3.73639710940879
1972-01-01	3.79178259189257
1973-01-01	3.84996717875456
1974-01-01	3.90793621027307
1975-01-01	3.96422113852393
1976-01-01	4.05195472116706
1977-01-01	4.13256329732944
1978-01-01	4.20840966338448
1979-01-01	4.28376384604716
1980-01-01	4.36116174562991
1981-01-01	4.46185788080722
1982-01-01	4.56320151923736
1983-01-01	4.66667667081966
1984-01-01	4.77324215985258
1985-01-01	4.88416541222151
1986-01-01	4.99860138888694
1987-01-01	5.11567643934431
1988-01-01	5.23460553604749
1989-01-01	5.35356416766502
1990-01-01	5.47145241239713
1991-01-01	5.60018559111243
1992-01-01	5.71856579896201
1993-01-01	5.83000010709161
1994-01-01	5.93847571060077
1995-01-01	6.04690460484150
1996-01-01	6.09974243582124
1997-01-01	6.14166477913436
1998-01-01	6.17509269036209
1999-01-01	6.20042644791236
2000-01-01	6.21933689696984
2001-01-01	6.35373324688863
2002-01-01	6.47884759671132
2003-01-01	6.59740695269662
2004-01-01	6.71633732245098
2005-01-01	6.84316643685353
2006-01-01	6.91310402243481
2007-01-01	6.97986839393423
2008-01-01	7.05822148707560
2009-01-01	7.16541388664537
2010-01-01	7.31496771048610
2011-01-01	7.66840608600032
2012-01-01	8.06346086854769
2013-01-01	8.48233173949942
2014-01-01	8.89878199519733
2015-01-01	9.29896823603701
2016-01-01	9.69627509532902
2017-01-01	10.06867058004780