Year % 1997 11.6564417177914 1999 11.8012422360248 2000 11.8012422360248 2001 11.8012422360248 2002 12.0481927710843 2003 12.0481927710843 2004 12.0481927710843 2005 12.1212121212121 2006 8.43373493975904 2007 8.43373493975904 2008 8.43373493975904 2009 8.43373493975904 2010 12.6506024096386 2011 12.1212121212121 2012 12.1212121212121 2013 12.1212121212121 2014 19.8795180722892 2015 19.8795180722892 2016 19.8795180722892 2017 18.6746987951807 2018 18.1286549707602 2019 18.7134502923977 2020 18.3431952662722 2021 18.8235294117647 2022 28.8770053475936 2023 28.8770053475936