Year	Percent of Total
1960-01-01	50.4679842463371
1961-01-01	50.0904166032645
1962-01-01	49.7616034499075
1963-01-01	49.5000015789186
1964-01-01	49.3361315237199
1965-01-01	49.2773688091696
1966-01-01	49.0898444471960
1967-01-01	49.0027002743711
1968-01-01	48.9915949650236
1969-01-01	49.0304327896275
1970-01-01	49.1046171050544
1971-01-01	49.0289390216663
1972-01-01	49.0394373850019
1973-01-01	49.0981457018775
1974-01-01	49.1641426308505
1975-01-01	49.2197125452032
1976-01-01	49.2040682120032
1977-01-01	49.1745045610655
1978-01-01	49.1573417109491
1979-01-01	49.1943033618240
1980-01-01	49.3016040623268
1981-01-01	49.3339727672849
1982-01-01	49.4552705593971
1983-01-01	49.6288711297384
1984-01-01	49.8098744923749
1985-01-01	49.9794332836041
1986-01-01	50.1082500899061
1987-01-01	50.2416881045505
1988-01-01	50.3864222629519
1989-01-01	50.5558109376613
1990-01-01	50.7559338150774
1991-01-01	50.9832153289316
1992-01-01	51.2218369628929
1993-01-01	51.4784475453364
1994-01-01	51.7613921343509
1995-01-01	52.0733305763077
1996-01-01	52.3747799236143
1997-01-01	52.7280679900519
1998-01-01	53.1148932514172
1999-01-01	53.5116523399139
2000-01-01	53.9094794017979
2001-01-01	54.3397706968456
2002-01-01	54.7684833670569
2003-01-01	55.2109728126434
2004-01-01	55.6934867985175
2005-01-01	56.2279834486799
2006-01-01	56.7756065646114
2007-01-01	57.3787372346449
2008-01-01	58.0207472495312
2009-01-01	58.6778304624219
2010-01-01	59.3371168810186
2011-01-01	60.0066334594569
2012-01-01	60.6748388070700
2013-01-01	61.3357111547584
2014-01-01	61.9793407268025
2015-01-01	62.5944429918259
2016-01-01	63.1740592724551
2017-01-01	63.7039537868426