Year Percent 1987 44.40639 1988 46.62087 1989 46.07475 1990 44.48899 1991 42.36585 1992 42.93888 1994 48.3494 1995 48.1405 1996 49.33853 1997 47.70535 1998 48.89267 2000 52.5302 2001 53.28902 2002 54.56259 2003 56.32761 2012 77.43312