Year	Percent of Total
1960-01-01	6.34804601626363
1961-01-01	6.10062060550371
1962-01-01	5.87626136710846
1963-01-01	5.68297173387242
1964-01-01	5.53142706892967
1965-01-01	5.42798948680333
1966-01-01	5.40273836340542
1967-01-01	5.41694241091964
1968-01-01	5.45824066901555
1969-01-01	5.50849092034877
1970-01-01	5.55712427204844
1971-01-01	5.63680727254178
1972-01-01	5.68564081126315
1973-01-01	5.71804358700536
1974-01-01	5.75290392382578
1975-01-01	5.79728511834937
1976-01-01	5.86729070220956
1977-01-01	5.94464910937077
1978-01-01	6.00518247247375
1979-01-01	6.01409265997727
1980-01-01	5.95941415939538
1981-01-01	5.87921191629724
1982-01-01	5.75106632273805
1983-01-01	5.60582771412533
1984-01-01	5.48418170833593
1985-01-01	5.41065698222537
1986-01-01	5.34847605841069
1987-01-01	5.31602211161138
1988-01-01	5.33448266318101
1989-01-01	5.43423397745039
1990-01-01	5.63195893916762
1991-01-01	6.07505710718006
1992-01-01	6.62191639968514
1993-01-01	7.23148715856630
1994-01-01	7.83333231820590
1995-01-01	8.38129735663787
1996-01-01	8.78160099614452
1997-01-01	9.08691941427717
1998-01-01	9.34623782925508
1999-01-01	9.64086633385313
2000-01-01	10.01567637090060
2001-01-01	10.43021908409830
2002-01-01	10.91635609251070
2003-01-01	11.39615999172910
2004-01-01	11.74723689700630
2005-01-01	11.89970411829360
2006-01-01	11.90430961635960
2007-01-01	11.73035905212860
2008-01-01	11.45140326385210
2009-01-01	11.18066845208590
2010-01-01	10.99359784187390
2011-01-01	10.86563028480160
2012-01-01	10.81660086567230
2013-01-01	10.82550633158560
2014-01-01	10.86087770368380
2015-01-01	10.90923738836800
2016-01-01	11.06428575336020
2017-01-01	11.23247282840520