Annual Percent of Total
1960-01-01 41.3557318926220
1961-01-01 41.0124268295055
1962-01-01 40.5666246023141
1963-01-01 40.0764781178606
1964-01-01 39.5252120117809
1965-01-01 38.9512854290875
1966-01-01 38.3197234607485
1967-01-01 37.6441277014891
1968-01-01 37.0274997049388
1969-01-01 36.5089121081746
1970-01-01 36.0721003707288
1971-01-01 35.7356980171490
1972-01-01 35.1663168216710
1973-01-01 34.4682616123340
1974-01-01 33.7551397491282
1975-01-01 33.1299836387633
1976-01-01 33.1674681884075
1977-01-01 33.1961215283678
1978-01-01 33.2781517285898
1979-01-01 33.4333432369115
1980-01-01 33.6757904144788
1981-01-01 32.1797021084532
1982-01-01 31.0772325484145
1983-01-01 30.2673202382068
1984-01-01 29.5836933124423
1985-01-01 28.9171366898332
1986-01-01 29.2022255058653
1987-01-01 29.1413810167613
1988-01-01 28.8960643902351
1989-01-01 28.6091324398640
1990-01-01 28.3132365750506
1991-01-01 27.9469774826612
1992-01-01 27.7249821903184
1993-01-01 27.6071344548873
1994-01-01 27.4814383892565
1995-01-01 27.2968419822575
1996-01-01 27.0306181840461
1997-01-01 26.6498069613623
1998-01-01 26.2509310902385
1999-01-01 25.9327031312835
2000-01-01 25.7296118135908
2001-01-01 24.5186306708209
2002-01-01 23.5353336668427
2003-01-01 22.7805967591557
2004-01-01 22.1935679411745
2005-01-01 21.7118780662371
2006-01-01 18.5955410923789
2007-01-01 16.2833411648803
2008-01-01 14.7172546428453
2009-01-01 13.7198104074731
2010-01-01 13.0841793674804
2011-01-01 13.2929724280168
2012-01-01 13.3599864996056
2013-01-01 13.4904528959023
2014-01-01 13.6817891029342
2015-01-01 13.8263392193312
2016-01-01 13.8818369027366
2017-01-01 13.8772913571518