Year % 2000 16.983104196948233 2001 16.514190737249763 2002 16.24116427885439 2003 15.9480636890073 2004 15.47283384020168 2005 15.233383134195677 2006 14.756741824276173 2007 14.526318729022385 2008 14.239420922289206 2009 13.876803488261421 2010 13.55823804983712 2011 13.287045317297542 2012 13.080237941766024 2013 12.827036687992598 2014 12.646891474702912 2015 12.561462792670346 2016 12.489451666864765 2017 12.266453196059869 2018 12.146940568955678 2019 12.017009282484944