Year	Percent of Total
1960-01-01	42.7014749412813
1961-01-01	42.9970116423271
1962-01-01	43.2310673005067
1963-01-01	43.4134446382477
1964-01-01	43.5478400571494
1965-01-01	43.6385482319639
1966-01-01	43.8947280720970
1967-01-01	44.0744100268792
1968-01-01	44.1924927225821
1969-01-01	44.2564493431720
1970-01-01	44.2664936716776
1971-01-01	44.4399479918261
1972-01-01	44.5463542080823
1973-01-01	44.6010623674890
1974-01-01	44.6231411129945
1975-01-01	44.6239600208651
1976-01-01	44.7455582788295
1977-01-01	44.8156924739241
1978-01-01	44.8478042305103
1979-01-01	44.8471484520913
1980-01-01	44.8161330257014
1981-01-01	44.9426750500998
1982-01-01	45.0014776906290
1983-01-01	45.0081002718231
1984-01-01	44.9776723687715
1985-01-01	44.9189551101573
1986-01-01	44.9741976046769
1987-01-01	44.9642202374044
1988-01-01	44.9046432147062
1989-01-01	44.8072288170317
1990-01-01	44.6783693982873
1991-01-01	44.6065544320697
1992-01-01	44.4919752019812
1993-01-01	44.3386913932763
1994-01-01	44.1463572468964
1995-01-01	43.9150618465114
1996-01-01	43.8125593357828
1997-01-01	43.6596569235360
1998-01-01	43.4694878059879
1999-01-01	43.2588446504440
2000-01-01	43.0395522490897
2001-01-01	42.9072088365720
2002-01-01	42.7541716809298
2003-01-01	42.5881304867777
2004-01-01	42.4111825703332
2005-01-01	42.2209276390892
2006-01-01	42.1072222032379
2007-01-01	41.9682554550400
2008-01-01	41.8067123610507
2009-01-01	41.6258548980189
2010-01-01	41.4270374159493
2011-01-01	41.2093125767998
2012-01-01	40.9693201731100
2013-01-01	40.7101680376679
2014-01-01	40.4343226854590
2015-01-01	40.1442848827763
2016-01-01	39.8772521295552
2017-01-01	39.5946929397270