Year Percent 1969 30.05 1970 59.39 1973 4.832 1974 13.35 1975 3.027 1976 0.5122 1977 40.26 1978 28.22 1979 9.577 1980 19.39 1981 49.01 1982 79.84 1983 52.11 1984 61.55 1985 34.66 1986 53.82 1987 54.76 1988 59 1989 38.28 1990 13.7 1991 43.15 1992 54.17 1993 27.99 1994 43.65 1995 18.69 1996 4.614 1997 5.766 1998 1.617 1999 1.491 2000 3.227 2001 3.447 2002 22.65 2003 4.925 2004 3.035 2005 3.755 2006 5.717 2007 10.75