Annual Percent of Total
1960-01-01 46.4761216325660
1961-01-01 46.9413345825490
1962-01-01 47.4998882148048
1963-01-01 48.0396437008679
1964-01-01 48.4089874192745
1965-01-01 48.5556947459184
1966-01-01 48.6803573981776
1967-01-01 48.6039705890038
1968-01-01 48.4059934028094
1969-01-01 48.2069532605055
1970-01-01 48.0691015143434
1971-01-01 48.0788122462565
1972-01-01 48.1329137145833
1973-01-01 48.2129701239768
1974-01-01 48.2831187543568
1975-01-01 48.3277762399157
1976-01-01 48.5161255228257
1977-01-01 48.6601389044480
1978-01-01 48.7715107375854
1979-01-01 48.8674181427805
1980-01-01 48.9522296723666
1981-01-01 48.9707766827759
1982-01-01 48.9616252044920
1983-01-01 48.9141044227766
1984-01-01 48.8088126268514
1985-01-01 48.6341250218808
1986-01-01 48.4601525662034
1987-01-01 48.2192708786278
1988-01-01 47.9102311096161
1989-01-01 47.5301570041631
1990-01-01 47.0778683661023
1991-01-01 46.5265478490848
1992-01-01 45.9015468543655
1993-01-01 45.2285569766282
1994-01-01 44.5523225343174
1995-01-01 43.9028232701953
1996-01-01 43.2403140135677
1997-01-01 42.6726982440272
1998-01-01 42.1515990362904
1999-01-01 41.6077904647401
2000-01-01 41.0141755014732
2001-01-01 40.7332566385710
2002-01-01 40.3152675100353
2003-01-01 39.8396096849741
2004-01-01 39.4205969706353
2005-01-01 39.1085932354615
2006-01-01 38.4476491829728
2007-01-01 37.9434248981017
2008-01-01 37.5165549897240
2009-01-01 37.0218372790679
2010-01-01 36.3665558232203
2011-01-01 36.8516180004470
2012-01-01 37.2582263459026
2013-01-01 37.5651978043874
2014-01-01 37.8276933556006
2015-01-01 38.0916624068114
2016-01-01 37.3640409164115
2017-01-01 36.5761974853896