Year Percent 1990 0.95528 1991 0.89938 1992 0.89591 1993 0.8713 1994 0.8489 1995 0.87964 1996 0.84608 1997 0.82166 1998 0.80077 1999 0.78392 2000 0.76342 2001 0.99177 2002 0.97479 2003 0.95896 2004 0.72095 2005 0.70111 2007 0.94001 2008 0.92347 2009 0.90989 2010 0.89625 2011 0.88366 2012 0.87578 2013 0.8678 2014 1.98278 2015 1.96777 2016 2.02228 2017 2.58713 2018 2.71812 2019 3.00047 2020 3.28197