|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 2.56 | 2.29 |
| 1987 | 3.34 | 2.05 |
| 1988 | 3.49 | 3.49 |
| 1989 | 3.02 | 3.02 |
| 1990 | 4.35 | 4.35 |
| 1991 | 2.89 | 4.89 |
| 1992 | 1.64 | 3.82 |
| 1993 | 1.32 | 4.44 |
| 1994 | 1.50 | 2.47 |
| 1995 | 1.35 | 4.37 |
| 1996 | 1.32 | 2.84 |
| 1997 | 5.12 | 6.74 |
| 1998 | 1.93 | 2.88 |
| 1999 | 2.35 | 3.27 |
| 2000 | 6.15 | 2.25 |
| 2001 | 6.59 | 8.96 |
| 2002 | 6.79 | 7.36 |
| 2003 | 7.45 | 8.56 |
| 2004 | 7.26 | 8.53 |
| 2005 | 7.10 | 7.90 |
| 2006 | 14.19 | 16.29 |
| 2007 | 6.83 | 19.13 |
| 2008 | 6.25 | 18.02 |
| 2009 | 6.22 | 8.38 |
| 2010 | 5.99 | 7.90 |
|
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