Year	Percent of Total
1960-01-01	10.5461864089893
1961-01-01	10.6464125529562
1962-01-01	10.7381396798268
1963-01-01	10.8308674803386
1964-01-01	10.9315473833674
1965-01-01	11.0457564964554
1966-01-01	11.2000349428768
1967-01-01	11.3568745759885
1968-01-01	11.5123584582981
1969-01-01	11.6566603653946
1970-01-01	11.7858965065483
1971-01-01	11.9554563950059
1972-01-01	12.0831012619871
1973-01-01	12.1828053638581
1974-01-01	12.2754378514350
1975-01-01	12.3713645588527
1976-01-01	12.4651648294908
1977-01-01	12.5666862203397
1978-01-01	12.6406802574207
1979-01-01	12.6306322793523
1980-01-01	12.5134627749187
1981-01-01	12.3962091095397
1982-01-01	12.1705755101193
1983-01-01	11.8942734211613
1984-01-01	11.6463814494319
1985-01-01	11.4707267552419
1986-01-01	11.4218249217302
1987-01-01	11.4189715370215
1988-01-01	11.4599102923426
1989-01-01	11.5406590312815
1990-01-01	11.6616472085467
1991-01-01	12.0258491230223
1992-01-01	12.4325195126281
1993-01-01	12.8562778760788
1994-01-01	13.2555025657250
1995-01-01	13.6011678799518
1996-01-01	13.9637421917762
1997-01-01	14.2539338882607
1998-01-01	14.4983823372560
1999-01-01	14.7440961569011
2000-01-01	15.0177398235452
2001-01-01	15.4142796478337
2002-01-01	15.8203469652832
2003-01-01	16.2079205540935
2004-01-01	16.5285849959481
2005-01-01	16.7550868662072
2006-01-01	16.9948499107313
2007-01-01	17.1576373884732
2008-01-01	17.2709507715091
2009-01-01	17.3818524812289
2010-01-01	17.5241085142129
2011-01-01	17.7368495139821
2012-01-01	17.9863298851113
2013-01-01	18.2627349496050
2014-01-01	18.5448728305416
2015-01-01	18.8217933112906
2016-01-01	19.1507891396344
2017-01-01	19.4521056296731