Year	Percent of Total
1960-01-01	3.88204592648249
1961-01-01	3.91026463123573
1962-01-01	3.89412109337870
1963-01-01	3.85045695416751
1964-01-01	3.79910872731881
1965-01-01	3.74649946853946
1966-01-01	3.80219339957294
1967-01-01	3.86176515154791
1968-01-01	3.91889266809240
1969-01-01	3.97173623737704
1970-01-01	4.01332241766041
1971-01-01	4.07840022617715
1972-01-01	4.13796654460101
1973-01-01	4.19328064888409
1974-01-01	4.25417776239830
1975-01-01	4.31997067399818
1976-01-01	4.42298624331057
1977-01-01	4.52976157276979
1978-01-01	4.63821185692980
1979-01-01	4.74468002397062
1980-01-01	4.84679179889705
1981-01-01	4.97062420597183
1982-01-01	5.08093930405048
1983-01-01	5.18091846875191
1984-01-01	5.27284650866273
1985-01-01	5.35798873758350
1986-01-01	5.43933829818147
1987-01-01	5.51164766868954
1988-01-01	5.58075944211913
1989-01-01	5.65527161708197
1990-01-01	5.74138907600872
1991-01-01	5.83456978355126
1992-01-01	5.94366747184702
1993-01-01	6.06446931281233
1994-01-01	6.19038341789351
1995-01-01	6.31858749736776
1996-01-01	6.48552802820132
1997-01-01	6.63977863815105
1998-01-01	6.78796792348316
1999-01-01	6.93696825235191
2000-01-01	7.08959601821964
2001-01-01	7.24952478037096
2002-01-01	7.40806220851942
2003-01-01	7.56281351592174
2004-01-01	7.70651174753674
2005-01-01	7.83928273987464
2006-01-01	7.97969884332689
2007-01-01	8.11244122703877
2008-01-01	8.24466564913878
2009-01-01	8.38628228763512
2010-01-01	8.54642626464052
2011-01-01	8.72914989763561
2012-01-01	8.92125672992317
2013-01-01	9.13506745597183
2014-01-01	9.38844016021686
2015-01-01	9.69110035790211
2016-01-01	10.04380777357390
2017-01-01	10.43960059313270