Year	Percent of Total
1960-01-01	47.9059318137029
1961-01-01	47.7698061974231
1962-01-01	47.7119307128927
1963-01-01	47.6918668327736
1964-01-01	47.6497035374475
1965-01-01	47.5527890111702
1966-01-01	47.3022495980938
1967-01-01	47.0185824312036
1968-01-01	46.7203425410087
1969-01-01	46.4240149285035
1970-01-01	46.1246203679228
1971-01-01	45.7113962953570
1972-01-01	45.2627314489442
1973-01-01	44.8159293712732
1974-01-01	44.4198929107630
1975-01-01	44.0938285795364
1976-01-01	43.5883520333690
1977-01-01	43.2356002214368
1978-01-01	42.9793061604226
1979-01-01	42.7434704742183
1980-01-01	42.4969581498005
1981-01-01	42.2993920749660
1982-01-01	42.0547720198805
1983-01-01	41.8074882140970
1984-01-01	41.6165697615754
1985-01-01	41.4983716548660
1986-01-01	41.4527592122640
1987-01-01	41.4237938805323
1988-01-01	41.3984469489384
1989-01-01	41.3480214361374
1990-01-01	41.2525019329612
1991-01-01	41.1375974057515
1992-01-01	40.9864697559250
1993-01-01	40.7893653363723
1994-01-01	40.5411477621487
1995-01-01	40.2421626390245
1996-01-01	39.9270411978252
1997-01-01	39.5784106479392
1998-01-01	39.1868249330459
1999-01-01	38.7381066963098
2000-01-01	38.2260169347691
2001-01-01	37.7347120865072
2002-01-01	37.1494193363808
2003-01-01	36.5098476270295
2004-01-01	35.8761794892474
2005-01-01	35.2796672725397
2006-01-01	34.6747872950209
2007-01-01	34.1679294836091
2008-01-01	33.7109071975951
2009-01-01	33.2320197159291
2010-01-01	32.7025800994126
2011-01-01	32.2238628182764
2012-01-01	31.6721372945497
2013-01-01	31.0960694367543
2014-01-01	30.5717561194179
2015-01-01	30.1338475782706
2016-01-01	29.7204826901608
2017-01-01	29.3988942194123