Year Percent 1999-01-01 3.82833453463197 2000-01-01 3.45717215947311 2001-01-01 3.06622405396943 2002-01-01 3.17421149352475 2003-01-01 3.39043685530198 2004-01-01 3.26609800059403 2005-01-01 3.39737440713427 2006-01-01 2.73754358254754 2007-01-01 2.24795265799377 2008-01-01 2.24326704974743 2009-01-01 3.30312222143878 2010-01-01 4.13297881753547 2011-01-01 4.43105361350053 2012-01-01 4.50068217945295 2013-01-01 5.04476372425248 2014-01-01 4.78630603162649