Year	Percent of Total
1960-01-01	4.88488800364976
1961-01-01	4.90247644093798
1962-01-01	4.93697592642683
1963-01-01	4.95982860203535
1964-01-01	4.96247315714498
1965-01-01	4.95131157420624
1966-01-01	4.99499341238472
1967-01-01	5.05049441349607
1968-01-01	5.11025846439263
1969-01-01	5.17838659935363
1970-01-01	5.23902315040349
1971-01-01	5.48707331316027
1972-01-01	5.68803628079290
1973-01-01	5.86350528676706
1974-01-01	6.02778254895225
1975-01-01	6.20240567670474
1976-01-01	6.36285092468038
1977-01-01	6.54661580768207
1978-01-01	6.75064273124291
1979-01-01	6.93704272423449
1980-01-01	7.09173641930228
1981-01-01	6.99553946031886
1982-01-01	6.85028627901730
1983-01-01	6.66875032557171
1984-01-01	6.45679049970032
1985-01-01	6.22785418293195
1986-01-01	6.38387106437794
1987-01-01	6.60193197826524
1988-01-01	6.91603271399727
1989-01-01	7.34703568737160
1990-01-01	7.89028177352180
1991-01-01	7.90946979907521
1992-01-01	7.96106915780160
1993-01-01	8.01688622145364
1994-01-01	8.02474724611438
1995-01-01	7.95870530148122
1996-01-01	7.98940434144212
1997-01-01	7.94288087656494
1998-01-01	7.85616282857397
1999-01-01	7.78770134658228
2000-01-01	7.76626418287918
2001-01-01	7.72417991340121
2002-01-01	7.71204701273262
2003-01-01	7.72161172161172
2004-01-01	7.70826839152120
2005-01-01	7.65524677267385
2006-01-01	7.61580104397679
2007-01-01	7.53962890738131
2008-01-01	7.44443375348792
2009-01-01	7.34256347319168
2010-01-01	7.24609990733399
2011-01-01	7.20913633119200
2012-01-01	7.17759596515012
2013-01-01	7.15425506803010
2014-01-01	7.14742384355021
2015-01-01	7.15669846381397
2016-01-01	7.22159583290625
2017-01-01	7.30442847206121