Year	Percent of Total
1960-01-01	4.13880156130225
1961-01-01	4.20971692517027
1962-01-01	4.28927360029853
1963-01-01	4.37183015713932
1964-01-01	4.45570863233312
1965-01-01	4.54332694103242
1966-01-01	4.59313763286887
1967-01-01	4.64927882312380
1968-01-01	4.71259483442113
1969-01-01	4.77875945093852
1970-01-01	4.84337600732092
1971-01-01	4.92310690104804
1972-01-01	4.99641306268996
1973-01-01	5.07036966855948
1974-01-01	5.14658658349562
1975-01-01	5.22012807415834
1976-01-01	5.35404310718935
1977-01-01	5.48462757795918
1978-01-01	5.61498658664812
1979-01-01	5.73856902727055
1980-01-01	5.84577872826456
1981-01-01	5.90877565646789
1982-01-01	5.95054615627418
1983-01-01	5.98383482843416
1984-01-01	6.01644116840252
1985-01-01	6.04423656516082
1986-01-01	6.06878771414388
1987-01-01	6.10697020706054
1988-01-01	6.16528711314534
1989-01-01	6.23992277872522
1990-01-01	6.32333726010829
1991-01-01	6.37695106480000
1992-01-01	6.41805116290365
1993-01-01	6.44884503241502
1994-01-01	6.47471031849047
1995-01-01	6.49894927109324
1996-01-01	6.56057433058845
1997-01-01	6.62126493900938
1998-01-01	6.68507806792558
1999-01-01	6.75304009571441
2000-01-01	6.82513251598710
2001-01-01	6.87472181623126
2002-01-01	6.92756027167530
2003-01-01	6.98380268697246
2004-01-01	7.04257926957818
2005-01-01	7.10535514657155
2006-01-01	7.20207704079412
2007-01-01	7.29594941704079
2008-01-01	7.39195049712064
2009-01-01	7.50002310258472
2010-01-01	7.62984843346168
2011-01-01	7.75711634747697
2012-01-01	7.90287753324199
2013-01-01	8.06342453418755
2014-01-01	8.23430444040373
2015-01-01	8.41570001150124
2016-01-01	8.61531116290493
2017-01-01	8.81721710507191