|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | | 6.81 |
| 1987 | | 6.95 |
| 1988 | | 6.54 |
| 1989 | | 6.64 |
| 1990 | | 6.74 |
| 1991 | | 6.34 |
| 1992 | | 2.55 |
| 1993 | | 2.45 |
| 1994 | | 2.37 |
| 1995 | | 2.29 |
| 1996 | | 2.20 |
| 1997 | | 2.08 |
| 1998 | | 2.00 |
| 1999 | | 2.00 |
| 2000 | | 1.94 |
| 2001 | | 1.84 |
| 2002 | | 1.88 |
| 2003 | | 1.51 |
| 2004 | | 1.69 |
| 2005 | | 1.90 |
| 2006 | | 1.84 |
| 2007 | | 1.88 |
| 2008 | | 2.45 |
| 2009 | | 10.26 |
| 2010 | | 10.26 |
|
|