|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | | 2.66 |
| 1987 | | 2.17 |
| 1988 | | 2.55 |
| 1989 | | 2.39 |
| 1990 | | 2.74 |
| 1991 | | 2.98 |
| 1992 | | 2.96 |
| 1993 | | 2.96 |
| 1994 | | 2.96 |
| 1995 | | 3.02 |
| 1996 | | 3.02 |
| 1997 | | 2.96 |
| 1998 | | 2.86 |
| 1999 | | 3.58 |
| 2000 | | 4.44 |
| 2001 | | 5.60 |
| 2002 | | 5.37 |
| 2003 | | 7.28 |
| 2004 | | 9.45 |
| 2005 | | 9.89 |
| 2006 | | 9.14 |
| 2007 | | 8.13 |
| 2008 | | 6.77 |
| 2009 | | 4.16 |
| 2010 | | 4.17 |
|
|