Year	Percent of Total
1960-01-01	4.31911030970636
1961-01-01	4.51791427944895
1962-01-01	4.73932885906040
1963-01-01	4.96385160224141
1964-01-01	5.18651985627159
1965-01-01	5.41671933522598
1966-01-01	5.44806837637564
1967-01-01	5.48183536469033
1968-01-01	5.51961977023860
1969-01-01	5.56289722041685
1970-01-01	5.61325938569283
1971-01-01	5.66633893832825
1972-01-01	5.72092196308923
1973-01-01	5.77246148370367
1974-01-01	5.81431547210908
1975-01-01	5.84291749866970
1976-01-01	6.03902028383254
1977-01-01	6.22713932646267
1978-01-01	6.41099434667639
1979-01-01	6.58904951024293
1980-01-01	6.75496811208274
1981-01-01	6.84684036962426
1982-01-01	6.91384303057226
1983-01-01	6.96474328243462
1984-01-01	7.01007862025417
1985-01-01	7.05491829004746
1986-01-01	7.09720034551090
1987-01-01	7.16086680040466
1988-01-01	7.24267965276449
1989-01-01	7.33419999003206
1990-01-01	7.43032255030645
1991-01-01	7.46379756180103
1992-01-01	7.48531047367486
1993-01-01	7.49563441072782
1994-01-01	7.49929667109555
1995-01-01	7.50031527839082
1996-01-01	7.55692931245324
1997-01-01	7.62111266041370
1998-01-01	7.69780731701059
1999-01-01	7.78524427279855
2000-01-01	7.87947745913980
2001-01-01	7.90336685206000
2002-01-01	7.93130339097871
2003-01-01	7.96678796878612
2004-01-01	8.01348003153061
2005-01-01	8.07440449190122
2006-01-01	8.14348839374570
2007-01-01	8.20798806110828
2008-01-01	8.27268485033988
2009-01-01	8.35039774157817
2010-01-01	8.45460579793484
2011-01-01	8.58245629163953
2012-01-01	8.74004573050540
2013-01-01	8.91855584897575
2014-01-01	9.10660647282909
2015-01-01	9.30317340161717
2016-01-01	9.49705954316632
2017-01-01	9.68387699680898