Year Percent 1983-01-01 0.49499799999999994 1984-01-01 1.00992000000000020 1985-01-01 2.39546000000000000 1986-01-01 3.01188000000000000 1987-01-01 3.08909000000000000 1988-01-01 2.12383000000000000 1989-01-01 1.56904000000000000 1990-01-01 1.48724000000000000 1991-01-01 2.08588000000000000 1992-01-01 2.78221000000000000 1993-01-01 3.74264000000000000 1994-01-01 4.10585000000000000 1995-01-01 4.70448000000000000 1996-01-01 6.92139000000000000 1997-01-01 8.58302000000000000 1998-01-01 12.72550000000000000 1999-01-01 9.12477000000000000 2000-01-01 7.81147000000000000 2001-01-01 7.79490000000000000 2002-01-01 7.65886999999999900 2003-01-01 8.10540000000000000 2004-01-01 8.42345000000000000 2005-01-01 8.14940000000000000 2006-01-01 8.72967000000000000 2007-01-01 9.04715000000000000 2008-01-01 10.04860000000000000 2009-01-01 12.93860000000000000 2010-01-01 11.46610000000000000 2011-01-01 11.89700000000000000 2012-01-01 12.82980000000000000 2013-01-01 13.42390000000000000 2014-01-01 12.82580000000000000 2015-01-01 12.28160000000000000 2016-01-01 11.87520000000000000