Year	Percent of Total
1960-01-01	4.14820125130344
1961-01-01	4.17938185696335
1962-01-01	4.20705660067362
1963-01-01	4.23405614791742
1964-01-01	4.24569948287070
1965-01-01	4.24900347722840
1966-01-01	4.27263665212580
1967-01-01	4.28069428175913
1968-01-01	4.28309251169644
1969-01-01	4.28220457651705
1970-01-01	4.29277635003519
1971-01-01	4.35280825046277
1972-01-01	4.40110106173810
1973-01-01	4.45341624514672
1974-01-01	4.50547190934223
1975-01-01	4.56250938015909
1976-01-01	4.57871798856060
1977-01-01	4.59087955967268
1978-01-01	4.58748605764041
1979-01-01	4.55680973780121
1980-01-01	4.49099927161736
1981-01-01	4.46105471450063
1982-01-01	4.40858085808581
1983-01-01	4.33507463644415
1984-01-01	4.25951218295322
1985-01-01	4.18260864292601
1986-01-01	4.14700886959804
1987-01-01	4.11943552088114
1988-01-01	4.11053019639386
1989-01-01	4.11186630983981
1990-01-01	4.13005459819143
1991-01-01	4.19252221047895
1992-01-01	4.27085638415579
1993-01-01	4.36401910776455
1994-01-01	4.45471404345627
1995-01-01	4.52641293371279
1996-01-01	4.39450382822591
1997-01-01	4.25349494147271
1998-01-01	4.12186691216064
1999-01-01	4.00667709788893
2000-01-01	3.90756727250672
2001-01-01	3.80298371662536
2002-01-01	3.70052554098686
2003-01-01	3.59120127819269
2004-01-01	3.47605301189109
2005-01-01	3.34795977082502
2006-01-01	3.41568442666648
2007-01-01	3.48952940111995
2008-01-01	3.57617624483530
2009-01-01	3.68395401507984
2010-01-01	3.82080047760006
2011-01-01	3.79535347153029
2012-01-01	3.77308056703128
2013-01-01	3.75819699518567
2014-01-01	3.75354711766479
2015-01-01	3.76244127273942
2016-01-01	3.80320149119508
2017-01-01	3.85261062076807