|
| year | production | change |
| 1980 | .15 | NA |
| 1981 | .14 | -8.23 % |
| 1982 | .15 | 11.65 % |
| 1983 | .15 | -0.57 % |
| 1984 | .16 | 3.91 % |
| 1985 | .15 | -3.51 % |
| 1986 | .15 | -1.83 % |
| 1987 | .15 | -0.07 % |
| 1988 | .16 | 6.52 % |
| 1989 | .17 | 7.04 % |
| 1990 | .17 | 0.79 % |
| 1991 | .17 | -0.80 % |
| 1992 | .18 | 5.55 % |
| 1993 | .17 | -2.72 % |
| 1994 | .18 | 1.67 % |
| 1995 | .20 | 11.95 % |
| 1996 | .20 | 1.85 % |
| 1997 | .21 | 2.05 % |
| 1998 | .21 | 2.80 % |
| 1999 | .19 | -11.84 % |
| 2000 | .22 | 16.22 % |
| 2001 | .28 | 28.03 % |
| 2002 | .32 | 15.99 % |
| 2003 | .36 | 13.10 % |
| 2004 | .50 | 39.02 % |
| 2005 | .59 | 17.06 % |
| 2006 | .62 | 4.97 % |
| 2007 | .66 | 5.82 % |
| 2008 | .66 | 0.15 % |
| 2009 | .57 | -13.02 % |
| 2010 | .64 | 11.84 % |
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