Year	Percent of Total
1960-01-01	41.7472316328792
1961-01-01	42.0777786900621
1962-01-01	42.4795897377698
1963-01-01	42.9238705775552
1964-01-01	43.3573666301920
1965-01-01	43.7642285897585
1966-01-01	44.3319031115778
1967-01-01	44.8506208761936
1968-01-01	45.3350172595632
1969-01-01	45.7987452894534
1970-01-01	46.2427924478071
1971-01-01	46.7538482666755
1972-01-01	47.1627375412999
1973-01-01	47.4947084342108
1974-01-01	47.7631649485511
1975-01-01	47.9647005318057
1976-01-01	48.1372899223726
1977-01-01	48.2238329558140
1978-01-01	48.2181657303078
1979-01-01	48.1004634244714
1980-01-01	47.8622852361230
1981-01-01	47.4157957166254
1982-01-01	46.8568181047645
1983-01-01	46.2141832948837
1984-01-01	45.5208362525572
1985-01-01	44.7954595264936
1986-01-01	44.2631798849995
1987-01-01	43.7158110938917
1988-01-01	43.1330498543035
1989-01-01	42.4816247215814
1990-01-01	41.7480397983979
1991-01-01	41.0548351525749
1992-01-01	40.2407308185501
1993-01-01	39.3568508664773
1994-01-01	38.4737970295796
1995-01-01	37.6243281701940
1996-01-01	36.8078176542589
1997-01-01	36.0566348964653
1998-01-01	35.3387988302189
1999-01-01	34.6014524010729
2000-01-01	33.8270020394899
2001-01-01	33.0398895997218
2002-01-01	32.2343584775437
2003-01-01	31.4456569429368
2004-01-01	30.7241199847356
2005-01-01	30.0943534331557
2006-01-01	29.6338053553257
2007-01-01	29.2501191720033
2008-01-01	28.9360057808606
2009-01-01	28.6685967267397
2010-01-01	28.4269282266248
2011-01-01	28.4170132530858
2012-01-01	28.4481543039996
2013-01-01	28.4997345048475
2014-01-01	28.5543707491875
2015-01-01	28.6020829340388
2016-01-01	28.4150025431998
2017-01-01	28.1594216812432