|
| year | production | consumption |
| 1980 | 33.00 | 107.00 |
| 1981 | 41.00 | 104.00 |
| 1982 | 43.00 | 102.00 |
| 1983 | 39.00 | 96.00 |
| 1984 | 38.00 | 101.00 |
| 1985 | 36.00 | 98.00 |
| 1986 | 31.00 | 104.00 |
| 1987 | 30.00 | 108.00 |
| 1988 | 24.40 | 120.00 |
| 1989 | 22.00 | 135.00 |
| 1990 | 19.61 | 145.00 |
| 1991 | 17.00 | 153.00 |
| 1992 | 15.00 | 165.00 |
| 1993 | 13.96 | 179.00 |
| 1994 | 12.41 | 196.00 |
| 1995 | 10.58 | 212.00 |
| 1996 | 9.18 | 232.00 |
| 1997 | 7.35 | 245.00 |
| 1998 | 8.08 | 255.00 |
| 1999 | 7.70 | 261.00 |
| 2000 | 6.76 | 239.63 |
| 2001 | 6.64 | 233.44 |
| 2002 | | 239.65 |
| 2003 | | 248.50 |
| 2004 | 5.59 | 263.42 |
| 2005 | 4.42 | 272.35 |
| 2006 | 2.99 | 278.67 |
| 2007 | 2.55 | 351.67 |
| 2008 | 3.09 | 369.88 |
| 2009 | 3.68 | 367.61 |
| 2010 | 4.16 | 322.39 |
| 2011 | 4.59 | 332.72 |
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