|
| year | production | change |
| 1980 | .01 | NA |
| 1981 | .02 | 31.35 % |
| 1982 | .02 | 4.84 % |
| 1983 | .02 | 15.73 % |
| 1984 | .02 | -1.33 % |
| 1985 | .02 | 15.85 % |
| 1986 | .02 | 4.34 % |
| 1987 | .02 | 3.60 % |
| 1988 | .03 | 18.86 % |
| 1989 | .03 | 6.47 % |
| 1990 | .03 | 3.30 % |
| 1991 | .03 | 7.18 % |
| 1992 | .03 | -0.68 % |
| 1993 | .04 | 5.85 % |
| 1994 | .04 | -0.95 % |
| 1995 | .04 | 6.49 % |
| 1996 | .04 | 5.54 % |
| 1997 | .04 | -4.34 % |
| 1998 | .04 | 0.90 % |
| 1999 | .03 | -22.08 % |
| 2000 | .02 | -29.64 % |
| 2001 | .03 | 56.39 % |
| 2002 | .04 | 17.53 % |
| 2003 | .04 | 14.99 % |
| 2004 | .04 | -5.28 % |
| 2005 | .04 | 2.76 % |
| 2006 | .05 | 5.12 % |
| 2007 | .05 | 4.34 % |
| 2008 | .04 | -10.14 % |
| 2009 | .04 | -12.39 % |
| 2010 | .05 | 35.61 % |
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