Year Number 1979 56.72627485189 1980 5.284761595012218 1981 9.223025114990403 1982 6.484256617688997 1983 17.791126464860298 1984 3.539508448431382 1985 1.777939360677792 1986 2.8369359639908134 1987 0.4945310446455647 2004 0.18341024591606817 2005 0.23127226617747373 2006 0.4589241211900509 2007 0.7443752796468552 2008 0.8353971213011805 2009 2.4158770310312674 2010 2.641188125778314 2011 2.3070690176128794 2012 2.477583891541423 2013 2.919542029353743 2014 2.48325765683866 2015 3.7957588545189487 2016 4.331653278253021 2017 4.727281025627733 2018 2.875377157301337 2019 2.5979142281695675 2020 2.7436183444980373 2021 4.502290872120515 2022 3.4367359561298354