Year	Percent
1998-01-01	2.56111705649975
1999-01-01	2.29339038226195
2000-01-01	2.07243163508173
2001-01-01	2.08254820696576
2002-01-01	2.59626595680428
2003-01-01	3.25691683379253
2004-01-01	3.42646955033074
2005-01-01	3.94339093786381
2006-01-01	3.99707475336019
2007-01-01	4.17975336465559
2008-01-01	3.95879223595889
2009-01-01	4.89732445755255
2010-01-01	5.59358373799660
2011-01-01	6.52091542411443
2012-01-01	7.95386906078120
2013-01-01	8.18417349185408
2014-01-01	6.98936370567851