|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 19.43 | 24.54 |
| 1987 | 19.43 | 24.54 |
| 1988 | 17.01 | 23.12 |
| 1989 | 17.01 | 23.14 |
| 1990 | 20.04 | 26.17 |
| 1991 | 21.88 | 26.52 |
| 1992 | 19.37 | 26.51 |
| 1993 | 17.79 | 26.58 |
| 1994 | 16.36 | 21.78 |
| 1995 | 13.09 | 18.81 |
| 1996 | 8.87 | 14.48 |
| 1997 | 8.67 | 12.01 |
| 1998 | 16.71 | 7.89 |
| 1999 | 16.03 | 21.35 |
| 2000 | 20.27 | 25.63 |
| 2001 | 4.23 | 5.79 |
| 2002 | 4.23 | 5.81 |
| 2003 | 4.11 | 5.83 |
| 2004 | 4.14 | 5.67 |
| 2005 | 3.50 | 4.78 |
| 2006 | 2.68 | 3.66 |
| 2007 | 3.21 | 4.37 |
| 2008 | 3.29 | 4.48 |
| 2009 | 2.52 | 3.44 |
| 2010 | 2.39 | 3.27 |
|
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