Year	Percent of Total
1960-01-01	44.5391090678846
1961-01-01	45.0386366021710
1962-01-01	45.6737307030969
1963-01-01	46.3224864532200
1964-01-01	46.8155745337700
1965-01-01	47.0844270256195
1966-01-01	47.3496346415679
1967-01-01	47.3569395449236
1968-01-01	47.1997114167405
1969-01-01	47.0120976174522
1970-01-01	46.8591825970991
1971-01-01	46.8439300809907
1972-01-01	46.8496613761782
1973-01-01	46.8563999911923
1974-01-01	46.8220169331007
1975-01-01	46.7303293852050
1976-01-01	46.7359819720947
1977-01-01	46.6676095624557
1978-01-01	46.5491777381977
1979-01-01	46.4120938377713
1980-01-01	46.2720336916745
1981-01-01	46.1835448090180
1982-01-01	46.0435248354357
1983-01-01	45.8614681569485
1984-01-01	45.6362660332103
1985-01-01	45.3629225151839
1986-01-01	45.0893178307969
1987-01-01	44.7531026661750
1988-01-01	44.3531974391794
1989-01-01	43.8831456834185
1990-01-01	43.3377275028561
1991-01-01	42.7668949947860
1992-01-01	42.1266561235541
1993-01-01	41.4100113297008
1994-01-01	40.6026347765814
1995-01-01	39.6963316666608
1996-01-01	38.7512161519601
1997-01-01	37.6979244944572
1998-01-01	36.5676061484193
1999-01-01	35.4133688153719
2000-01-01	34.2723785469698
2001-01-01	33.0697594431123
2002-01-01	31.9497837258931
2003-01-01	30.9069720030982
2004-01-01	29.9429114398130
2005-01-01	29.0824318366164
2006-01-01	28.4077924880799
2007-01-01	27.8876495783858
2008-01-01	27.5186495744565
2009-01-01	27.2946103509413
2010-01-01	27.2104484576330
2011-01-01	27.4219342882932
2012-01-01	27.6670881399267
2013-01-01	27.9634405693150
2014-01-01	28.3036468938338
2015-01-01	28.6530152543941
2016-01-01	29.0052379384236
2017-01-01	29.2848986287912