Year	Percent
1969-01-01	2.58499620773439
1970-01-01	1.89908468384622
1971-01-01	1.81283996783605
1972-01-01	1.93474585443021
1973-01-01	1.74283150255761
1974-01-01	1.96566811459914
1975-01-01	2.31426822937215
1976-01-01	2.44778113101513
1977-01-01	2.26612756385416
1978-01-01	2.79668133944704
1979-01-01	3.07154473322514
1980-01-01	2.80598684815359
1981-01-01	3.56662722230509
1982-01-01	4.61295245035026
1983-01-01	5.08989530834761
1984-01-01	3.58063279298361
1985-01-01	3.55089029339877
1986-01-01	3.07384480071149
1987-01-01	4.07220923953005
1988-01-01	3.99066168331041
1989-01-01	3.57686114144962
1990-01-01	3.58089634949970
1991-01-01	3.65250862816506
1992-01-01	3.78492449754082
1993-01-01	4.47155484364638
1994-01-01	3.96183016310870
1995-01-01	4.34681913798446
1996-01-01	4.47461579431249
1997-01-01	4.64739347255793
1998-01-01	4.58215913983994
1999-01-01	3.82976566756620
2000-01-01	3.84116042938358
2001-01-01	3.80192543939768
2002-01-01	3.88367103831189
2003-01-01	4.21736673095890
2004-01-01	5.90821885708239
2005-01-01	5.85594015401840
2006-01-01	5.60227520678594
2007-01-01	5.30005282314684
2008-01-01	4.40870892794992
2009-01-01	5.08359679898467
2010-01-01	4.63023068310929
2011-01-01	4.58508517464983
2012-01-01	4.78562286402070
2013-01-01	5.29411199087527
2014-01-01	5.38180479267647
2015-01-01	5.30980854893741
2016-01-01	5.54286150548398
2017-01-01	5.03365693843332