Year	Percent of Total
1960-01-01	5.62079727573234
1961-01-01	5.72911758561379
1962-01-01	5.83669213553844
1963-01-01	5.94543396032157
1964-01-01	6.05533703441394
1965-01-01	6.16701867670892
1966-01-01	6.30784971730746
1967-01-01	6.45261222470882
1968-01-01	6.59804563006273
1969-01-01	6.73944915318518
1970-01-01	6.87543259800785
1971-01-01	7.04508531709701
1972-01-01	7.20188761612550
1973-01-01	7.35476337981368
1974-01-01	7.51830712346839
1975-01-01	7.70149770436322
1976-01-01	7.91975762746219
1977-01-01	8.16629820918168
1978-01-01	8.42786441010016
1979-01-01	8.68092604507198
1980-01-01	8.91420757089896
1981-01-01	9.17069342424550
1982-01-01	9.39706338028216
1983-01-01	9.61270083939476
1984-01-01	9.84553860522492
1985-01-01	10.11088991899670
1986-01-01	10.39838735421810
1987-01-01	10.71436188227310
1988-01-01	11.06343261482940
1989-01-01	11.44747527911970
1990-01-01	11.86864989509220
1991-01-01	12.30804078261080
1992-01-01	12.77820040989460
1993-01-01	13.27170267845870
1994-01-01	13.77996559090290
1995-01-01	14.29750692274400
1996-01-01	14.83226734664820
1997-01-01	15.36953513681370
1998-01-01	15.90812088972420
1999-01-01	16.44625820952960
2000-01-01	16.98470463555210
2001-01-01	17.50754538046570
2002-01-01	18.03083278585300
2003-01-01	18.55935146349130
2004-01-01	19.09800823675290
2005-01-01	19.65288133587890
2006-01-01	20.17814518907810
2007-01-01	20.69780634878490
2008-01-01	21.23581028555720
2009-01-01	21.82916023352520
2010-01-01	22.49897206865280
2011-01-01	23.15940671099740
2012-01-01	23.88070273784240
2013-01-01	24.62982683271490
2014-01-01	25.35239671164360
2015-01-01	26.01536466220210
2016-01-01	26.56456282978420
2017-01-01	27.04857729707430