Year	Percent
1972	8.26551
1973	7.54781
1974	5.41779
1975	8.19408
1976	7.56206
1977	8.21632
1978	8.87086
1979	5.99337
1980	5.17028
1981	6.97904
1982	5.92293
1983	6.03398
1984	6.4371
1985	7.32981
1986	6.78425
1987	6.00534
1988	5.43455
1989	5.36975
1990	5.57224
1991	6.16189
1992	6.88118
1993	3.86025
1994	4.37124
1995	6.2208
1996	7.94632
1997	10.15796
1998	8.64438
1999	8.32782
2000	5.86128
2001	5.7469
2002	4.99438
2003	5.20133
2004	5.19532
2005	6.65759
2006	6.21768
2007	5.93769
2008	6.19781
2009	7.35848