Year	Percent of Total
1960-01-01	8.36528855118820
1961-01-01	8.31443844987175
1962-01-01	8.26138492963508
1963-01-01	8.21978450332550
1964-01-01	8.20547401450895
1965-01-01	8.22773863289690
1966-01-01	8.36257117946415
1967-01-01	8.52452965076193
1968-01-01	8.70277894774087
1969-01-01	8.87909479104387
1970-01-01	9.04106302336283
1971-01-01	9.26235562992737
1972-01-01	9.45041554818109
1973-01-01	9.62776763435798
1974-01-01	9.81896268301999
1975-01-01	10.03118508139190
1976-01-01	10.24313114122860
1977-01-01	10.47099327851390
1978-01-01	10.67015014120320
1979-01-01	10.77917871918800
1980-01-01	10.77497475577880
1981-01-01	10.68133846103890
1982-01-01	10.49003507636740
1983-01-01	10.26112968080290
1984-01-01	10.07958250871500
1985-01-01	9.99295214583279
1986-01-01	10.01313251315940
1987-01-01	10.09767200214280
1988-01-01	10.24196994628370
1989-01-01	10.44062018044840
1990-01-01	10.69273237552960
1991-01-01	11.03199307915240
1992-01-01	11.41796832420770
1993-01-01	11.81375244963240
1994-01-01	12.16593739233520
1995-01-01	12.44544141234910
1996-01-01	12.75552295997100
1997-01-01	12.96684294873230
1998-01-01	13.12226647480760
1999-01-01	13.28704217801400
2000-01-01	13.49556842835270
2001-01-01	13.81488289075590
2002-01-01	14.16595595939770
2003-01-01	14.49037140861850
2004-01-01	14.69650100827720
2005-01-01	14.73545355459100
2006-01-01	14.73166230167320
2007-01-01	14.58591629281910
2008-01-01	14.35854079341510
2009-01-01	14.14017715556190
2010-01-01	13.98559136736120
2011-01-01	13.97864498072560
2012-01-01	14.02641333737340
2013-01-01	14.11489432003830
2014-01-01	14.22142530230570
2015-01-01	14.33534350182570
2016-01-01	14.56476669618130
2017-01-01	14.79927100194350