Year Number 1996 17.3913040161133 1998 13.043478012085 2000 11.4130430221558 2002 9.72972965240479 2003 14.5945949554443 2004 9.45273590087891 2005 13.7254905700684 2006 14.7058820724487 2007 16.5048542022705 2008 16.990291595459 2009 20.0956935882568 2010 19.1387557983398 2011 11.8483409881592 2012 16.5876770019531 2013 15.1658763885498 2014 8.17307662963867 2015 4.7619047164917 2016 2.38095235824585 2017 3.33333325386047 2018 2.85714292526245 2019 1.90476191043854 2020 0.476190477609634 2021 0 2022 0.471698105335236