year spills importexport domestic
1974 2 0.720 0.22
1975 5 0.850 0.17
1976 3 1.120 0.15
1977 3 1.345 0.20
1978 1 1.290 0.59
1979 5 1.260 0.64
1980 2 1.015 0.84
1981 2 0.870 0.87
1982 1 0.750 0.94
1983 1 0.605 0.99
1984 1 0.570 0.92
1985 2 0.540 1.00
1986 3 0.720 0.99
1987 4 0.790 1.06
1988 2 0.840 1.00
1989 2 0.995 0.88
1990 3 1.030 0.82
1991 2 0.975 0.82
1992 1 1.070 0.76
1993 0 1.190 0.66
1994 0 1.290 0.65
1995 1 1.235 0.59
1996 0 1.340 0.56
1997 0 1.440 0.51
1998 0 1.450 0.42
1999 0 1.510 0.44