Year	Percent
1970	25.98167
1971	22.7552
1972	22.26422
1973	39.23144
1974	23.00494
1975	32.88129
1976	22.76483
1977	20.91771
1978	23.14974
1979	22.13481
1980	5.64362
1981	15.98597
1982	7.02197
1983	13.74035
1984	3.90601
1985	6.36052
1986	2.03468
1987	-0.32354
1988	-0.53068
1989	-0.90568
1990	0.68067
1991	2.73727
1992	0.60612
1993	4.16212
1994	5.04316
1995	1.03488
1996	7.52813
1997	2.4502
1998	2.14388
1999	2.5638
2000	1.93944
2001	0.20066
2002	1.42268