Year	Percent of Total
1960-01-01	50.9185285967307
1961-01-01	50.8524471868580
1962-01-01	50.7473116970713
1963-01-01	50.6722050695901
1964-01-01	50.7384556845052
1965-01-01	51.0053963639260
1966-01-01	51.2147961219045
1967-01-01	51.6916842936874
1968-01-01	52.3300164177311
1969-01-01	52.9960169556158
1970-01-01	53.6478708098945
1971-01-01	54.5873144052272
1972-01-01	55.3458470201783
1973-01-01	56.0119467988335
1974-01-01	56.7310483802107
1975-01-01	57.5658672668237
1976-01-01	58.5799990958498
1977-01-01	59.5115578107382
1978-01-01	60.2029598398842
1979-01-01	60.5815945613423
1980-01-01	60.7449450379957
1981-01-01	61.3234853573725
1982-01-01	61.9355804273874
1983-01-01	62.5808732154319
1984-01-01	63.2449992605466
1985-01-01	63.8989251419132
1986-01-01	64.4220198010513
1987-01-01	64.9657631982046
1988-01-01	65.4952470933035
1989-01-01	65.9532590149886
1990-01-01	66.3048790189683
1991-01-01	66.6871950574623
1992-01-01	66.8884054384481
1993-01-01	66.9825558533104
1994-01-01	67.1002758188625
1995-01-01	67.3148024272752
1996-01-01	67.2502600818951
1997-01-01	67.4240560070702
1998-01-01	67.7178848399917
1999-01-01	67.9667124315441
2000-01-01	68.1025528521826
2001-01-01	68.3647188204875
2002-01-01	68.4133624893078
2003-01-01	68.3728786081651
2004-01-01	68.4349543505388
2005-01-01	68.6847740962993
2006-01-01	68.8851378310200
2007-01-01	69.2810907755908
2008-01-01	69.7664716899071
2009-01-01	70.1749323164183
2010-01-01	70.4277798478310
2011-01-01	70.6815142487388
2012-01-01	70.7798409249935
2013-01-01	70.7598244230417
2014-01-01	70.7018427179354
2015-01-01	70.6456597134001
2016-01-01	70.6504549444907
2017-01-01	70.6671525161682