Year Measure 1990 0.0175 1991 0.01949 1992 0.01313 1993 0.01841 1994 0.02028 1995 0.01674 1996 0.01462 1997 0.01683 1998 0.02714 1999 0.02495 2000 0.01983 2001 0.02135 2002 0.01723 2003 0.01667 2004 0.02138 2005 0.02265 2006 0.02378 2007 0.01884 2008 0.02128 2009 0.02245 2010 0.02488