Year	Percent of Total
1960-01-01	43.2307398324632
1961-01-01	43.6043314047490
1962-01-01	43.9128787753858
1963-01-01	44.1492625760375
1964-01-01	44.3163938636947
1965-01-01	44.4263869708880
1966-01-01	44.6665418295974
1967-01-01	44.8625176810154
1968-01-01	45.0041400614299
1969-01-01	45.0867397072141
1970-01-01	45.0988388414041
1971-01-01	44.6201871244646
1972-01-01	44.1688467920100
1973-01-01	43.7051511793522
1974-01-01	43.1827569164849
1975-01-01	42.5906847828117
1976-01-01	41.7267645965448
1977-01-01	40.8392848798380
1978-01-01	39.9816983449004
1979-01-01	39.2393602044553
1980-01-01	38.6457583536088
1981-01-01	38.0211056164062
1982-01-01	37.5652429624443
1983-01-01	37.2091849111936
1984-01-01	36.8361103982869
1985-01-01	36.3847167611666
1986-01-01	36.0873045562691
1987-01-01	35.6539805165168
1988-01-01	35.1654263719046
1989-01-01	34.7513119453534
1990-01-01	34.4674504649353
1991-01-01	34.0822600354561
1992-01-01	33.8352184172348
1993-01-01	33.6588128629203
1994-01-01	33.4409608103409
1995-01-01	33.1307837026314
1996-01-01	32.7505853513272
1997-01-01	32.3225021151135
1998-01-01	31.8778048001417
1999-01-01	31.4663780540091
2000-01-01	31.0991840098285
2001-01-01	30.6512394228263
2002-01-01	30.2096237057090
2003-01-01	29.7706946124580
2004-01-01	29.3296491994648
2005-01-01	28.8848018590048
2006-01-01	28.3504822396173
2007-01-01	27.8407004068650
2008-01-01	27.3344977028773
2009-01-01	26.8181990867805
2010-01-01	26.2953143402820
2011-01-01	25.8340480019834
2012-01-01	25.3465360211837
2013-01-01	24.8582682986433
2014-01-01	24.4115755151743
2015-01-01	24.0305966882647
2016-01-01	23.7072558123327
2017-01-01	23.4799771461284