Year	Percent of Total
1960-01-01	53.2799171172260
1961-01-01	53.1089534334546
1962-01-01	53.0962968691959
1963-01-01	53.1609248912018
1964-01-01	53.1975410502644
1965-01-01	53.1734640425734
1966-01-01	52.9058703899332
1967-01-01	52.6122427906418
1968-01-01	52.3235681217173
1969-01-01	52.0839498474935
1970-01-01	51.9042319846393
1971-01-01	51.6383372305354
1972-01-01	51.4658273787198
1973-01-01	51.3692618194586
1974-01-01	51.3423395995700
1975-01-01	51.3950648162567
1976-01-01	51.3279330754852
1977-01-01	51.3418299903139
1978-01-01	51.4282728696000
1979-01-01	51.5558427592584
1980-01-01	51.6825729390814
1981-01-01	51.7569476519448
1982-01-01	51.8891364686224
1983-01-01	52.0542743350743
1984-01-01	52.2469697813967
1985-01-01	52.4744130098957
1986-01-01	52.5866402895661
1987-01-01	52.7441722324808
1988-01-01	52.9417258893215
1989-01-01	53.1696852171095
1990-01-01	53.4176313519175
1991-01-01	53.5359187803542
1992-01-01	53.6959997165002
1993-01-01	53.8855763356205
1994-01-01	54.0937959387328
1995-01-01	54.3164101573065
1996-01-01	54.4581489348529
1997-01-01	54.6104075618503
1998-01-01	54.7819049533684
1999-01-01	54.9841072536863
2000-01-01	55.2170147129997
2001-01-01	55.3088686542642
2002-01-01	55.4599252117566
2003-01-01	55.6439932699434
2004-01-01	55.8299711777113
2005-01-01	56.0071950578054
2006-01-01	56.1636245855176
2007-01-01	56.3179321849505
2008-01-01	56.4873271572933
2009-01-01	56.6865118817147
2010-01-01	56.9119647991050
2011-01-01	57.0617562534144
2012-01-01	57.2346868029513
2013-01-01	57.4215321944667
2014-01-01	57.6153943525324
2015-01-01	57.8173929345370
2016-01-01	57.9346813994165
2017-01-01	58.0934401285388