Year	Percent of Total
1960-01-01	3.70386410893258
1961-01-01	3.72617322719271
1962-01-01	3.68735551435421
1963-01-01	3.60975115736686
1964-01-01	3.52103989532172
1965-01-01	3.43168471633119
1966-01-01	3.49753890283434
1967-01-01	3.57275195152894
1968-01-01	3.64818037728067
1969-01-01	3.71171944905093
1970-01-01	3.76091478205544
1971-01-01	3.83292431712805
1972-01-01	3.89977605404118
1973-01-01	3.96422450714689
1974-01-01	4.03229217665838
1975-01-01	4.10814148404547
1976-01-01	4.22214667809907
1977-01-01	4.33848706225556
1978-01-01	4.45826994076027
1979-01-01	4.58058952587570
1980-01-01	4.70382606883339
1981-01-01	4.85408647041553
1982-01-01	4.99379519791784
1983-01-01	5.12246505753333
1984-01-01	5.23666662018974
1985-01-01	5.33376802183308
1986-01-01	5.41358199110688
1987-01-01	5.47428910760999
1988-01-01	5.52519115176397
1989-01-01	5.58087174168830
1990-01-01	5.65204923863392
1991-01-01	5.72044404765979
1992-01-01	5.81514370026946
1993-01-01	5.92761893901688
1994-01-01	6.04471388832518
1995-01-01	6.16109366207689
1996-01-01	6.33147368465609
1997-01-01	6.48080814484139
1998-01-01	6.61913001913115
1999-01-01	6.76015008135064
2000-01-01	6.90838740308527
2001-01-01	7.06880220517916
2002-01-01	7.23355273588035
2003-01-01	7.39907142262479
2004-01-01	7.55407542665446
2005-01-01	7.69477818527575
2006-01-01	7.83004114776241
2007-01-01	7.95858563207336
2008-01-01	8.08861360806352
2009-01-01	8.23253893357358
2010-01-01	8.40025323913070
2011-01-01	8.59206316121283
2012-01-01	8.79140717054487
2013-01-01	9.02000139410578
2014-01-01	9.30929170209179
2015-01-01	9.67614467934214
2016-01-01	10.12290075179280
2017-01-01	10.64142459818110