Year % 2000 21.215964833505 2001 17.9071007297324 2002 11.0172196258194 2003 8.38582572565641 2004 6.07354427319199 2005 5.27560000618114 2006 3.99876150251155 2007 3.01859191826486 2008 3.09119803439691 2009 5.8712072518763 2010 11.421782175376 2011 11.7997140822193 2012 13.4656882284517 2013 15.1198478740683 2014 14.1653123764986 2015 13.7084158662801 2016 11.7777190845963 2017 10.0462751524632 2018 8.77033547967657 2019 7.41165705829786 2020 6.12240215634338 2021 5.77886406049307 2022 4.53846610334628