Year	Percent of Total
1960-01-01	61.8278899595200
1961-01-01	61.7120787833086
1962-01-01	61.6949054432498
1963-01-01	61.7494133365143
1964-01-01	61.8251821311836
1965-01-01	61.8977805739442
1966-01-01	61.9002308582670
1967-01-01	61.9250428291910
1968-01-01	61.9615147982572
1969-01-01	62.0281580585624
1970-01-01	62.1029279748997
1971-01-01	62.2001624330840
1972-01-01	62.3035589347524
1973-01-01	62.4172749246969
1974-01-01	62.5717420362107
1975-01-01	62.7664371755423
1976-01-01	62.8608692641072
1977-01-01	63.0220274037684
1978-01-01	63.2360670503462
1979-01-01	63.4858896275544
1980-01-01	63.7607827929587
1981-01-01	64.0673395106414
1982-01-01	64.3808811931631
1983-01-01	64.6874625397964
1984-01-01	64.9752169611168
1985-01-01	65.2342533720825
1986-01-01	65.3703484037883
1987-01-01	65.5018991009068
1988-01-01	65.6250696354922
1989-01-01	65.7328264496994
1990-01-01	65.8207104462660
1991-01-01	65.8576493294435
1992-01-01	65.8829924462340
1993-01-01	65.9061234739362
1994-01-01	65.9460424607016
1995-01-01	66.0116937299619
1996-01-01	66.0416567710462
1997-01-01	66.1067917796670
1998-01-01	66.1932769037099
1999-01-01	66.2804067085803
2000-01-01	66.3567459071562
2001-01-01	66.4344229896542
2002-01-01	66.4955307824131
2003-01-01	66.5473826185207
2004-01-01	66.6014486928737
2005-01-01	66.6591849383845
2006-01-01	66.6614123557783
2007-01-01	66.6723944227935
2008-01-01	66.6747299954416
2009-01-01	66.6424018106688
2010-01-01	66.5625138551709
2011-01-01	66.4193574857623
2012-01-01	66.2575263807633
2013-01-01	66.0727760637157
2014-01-01	65.8699578108874
2015-01-01	65.6546191676991
2016-01-01	65.4577886504858
2017-01-01	65.2443668876614