Year	Percent of Total
1960-01-01	10.5743557668016
1961-01-01	10.6228506808302
1962-01-01	10.6526530757892
1963-01-01	10.6873556499833
1964-01-01	10.7590770857830
1965-01-01	10.8849326030100
1966-01-01	11.0823861590729
1967-01-01	11.3144955713977
1968-01-01	11.5637741715397
1969-01-01	11.8040039959362
1970-01-01	12.0214868102289
1971-01-01	12.2582530845872
1972-01-01	12.4358476545394
1973-01-01	12.5729070970225
1974-01-01	12.6991480174528
1975-01-01	12.8290427449831
1976-01-01	12.9532455530036
1977-01-01	13.0945399437941
1978-01-01	13.2052460866337
1979-01-01	13.2095145387551
1980-01-01	13.0724978533623
1981-01-01	12.9247064317726
1982-01-01	12.6329591464792
1983-01-01	12.2746358480662
1984-01-01	11.9583543120470
1985-01-01	11.7431321347933
1986-01-01	11.6549347059414
1987-01-01	11.6414829805029
1988-01-01	11.6864120255670
1989-01-01	11.7671149777546
1990-01-01	11.8750638034673
1991-01-01	12.2274222090692
1992-01-01	12.6162963324818
1993-01-01	13.0179079627514
1994-01-01	13.3943644142093
1995-01-01	13.7210565949883
1996-01-01	14.0585963107521
1997-01-01	14.3187834192448
1998-01-01	14.5331071565372
1999-01-01	14.7482029326146
2000-01-01	14.9884466791910
2001-01-01	15.4094435143091
2002-01-01	15.8262493504801
2003-01-01	16.2233956045148
2004-01-01	16.5733668881960
2005-01-01	16.8574540749198
2006-01-01	17.2036690255314
2007-01-01	17.5143437533830
2008-01-01	17.7820976379461
2009-01-01	18.0019754729971
2010-01-01	18.1781326456641
2011-01-01	18.4357605975265
2012-01-01	18.6593036884901
2013-01-01	18.8638288030482
2014-01-01	19.0689565379131
2015-01-01	19.2836420408268
2016-01-01	19.5254576180012
2017-01-01	19.7544199787656