Year	Percent
1999-01-01	6.54661414368786
2000-01-01	5.24959560621450
2001-01-01	5.08490372607132
2002-01-01	4.97076023391813
2003-01-01	6.06436341092262
2004-01-01	5.99165928550340
2005-01-01	5.27734692370190
2006-01-01	4.53285683028226
2007-01-01	4.19770669003798
2008-01-01	3.73540435346692
2009-01-01	5.31446144992177
2010-01-01	6.46481474774546
2011-01-01	7.46583873355115
2012-01-01	7.54583665483006
2013-01-01	7.27414584580770
2014-01-01	6.82008216090450
2015-01-01	6.44623607210798
2016-01-01	6.63965631657993
2017-01-01	5.93605690121906