|
| year | production | change |
| 1980 | .38 | NA |
| 1981 | .33 | -13.44 % |
| 1982 | .34 | 3.44 % |
| 1983 | .35 | 1.83 % |
| 1984 | .35 | 0.44 % |
| 1985 | .38 | 8.12 % |
| 1986 | .36 | -3.67 % |
| 1987 | .34 | -5.59 % |
| 1988 | .35 | 2.58 % |
| 1989 | .46 | 29.53 % |
| 1990 | .59 | 29.09 % |
| 1991 | .64 | 8.85 % |
| 1992 | .65 | 1.49 % |
| 1993 | .68 | 4.61 % |
| 1994 | .72 | 5.11 % |
| 1995 | .80 | 10.98 % |
| 1996 | .81 | 1.15 % |
| 1997 | .81 | 0.31 % |
| 1998 | .77 | -4.89 % |
| 1999 | .72 | -5.84 % |
| 2000 | .69 | -4.64 % |
| 2001 | .59 | -14.16 % |
| 2002 | .55 | -6.71 % |
| 2003 | .53 | -3.84 % |
| 2004 | .53 | -0.67 % |
| 2005 | .58 | 10.66 % |
| 2006 | .52 | -10.49 % |
| 2007 | .54 | 2.46 % |
| 2008 | .55 | 2.01 % |
| 2009 | .53 | -2.66 % |
| 2010 | .54 | 1.37 % |
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