|
| year | production | change |
| 1980 | .02 | NA |
| 1981 | .01 | -10.73 % |
| 1982 | .02 | 24.72 % |
| 1983 | .02 | 29.46 % |
| 1984 | .02 | -26.60 % |
| 1985 | .01 | -20.35 % |
| 1986 | .03 | 106.72 % |
| 1987 | .03 | -7.94 % |
| 1988 | .03 | -2.53 % |
| 1989 | .03 | 18.92 % |
| 1990 | .03 | 8.31 % |
| 1991 | .04 | 4.21 % |
| 1992 | .03 | -7.25 % |
| 1993 | .04 | 18.33 % |
| 1994 | .04 | 11.01 % |
| 1995 | .04 | 4.06 % |
| 1996 | .05 | 15.83 % |
| 1997 | .06 | 11.98 % |
| 1998 | .07 | 28.35 % |
| 1999 | .08 | 10.24 % |
| 2000 | .08 | -4.09 % |
| 2001 | .08 | -2.69 % |
| 2002 | .07 | -12.23 % |
| 2003 | .08 | 24.09 % |
| 2004 | .09 | 8.31 % |
| 2005 | .09 | -1.32 % |
| 2006 | .09 | 3.35 % |
| 2007 | .08 | -9.88 % |
| 2008 | .08 | 2.35 % |
| 2009 | .08 | -5.54 % |
| 2010 | .09 | 6.96 % |
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