Year	Percent
1979-01-01	5.19973183493458
1980-01-01	5.38533482194301
1981-01-01	5.69209572880549
1982-01-01	5.86473389171829
1983-01-01	5.88958028225390
1984-01-01	6.04617705057959
1985-01-01	6.55488654778810
1986-01-01	6.38895120880912
1987-01-01	6.71265743763084
1988-01-01	6.95244819900193
1989-01-01	7.06247814525877
1990-01-01	6.72477808846303
1991-01-01	6.92263422504814
1992-01-01	7.56214867446114
1993-01-01	7.75842528078939
1994-01-01	8.40141862090529
1995-01-01	8.27855689431737
1996-01-01	8.42436579626480
1997-01-01	8.93608454096354
1998-01-01	9.19275629310851
1999-01-01	9.57085928828017
2000-01-01	9.77623069087525
2001-01-01	9.86278206234029
2002-01-01	9.82094954067306
2003-01-01	10.15546574223010
2004-01-01	10.12671451513530
2005-01-01	9.68927497523276
2006-01-01	9.67074991533569
2007-01-01	9.21680064933097
2008-01-01	9.06685217363283
2009-01-01	9.64565237283426
2010-01-01	9.43733070921128
2011-01-01	9.40026338771664
2012-01-01	9.86286768497558
2013-01-01	9.86182572862819
2014-01-01	10.13747892585680
2015-01-01	9.70302684508251
2016-01-01	9.84452852181985
2017-01-01	9.68472466030028