|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 2.89 | 2.94 |
| 1987 | 2.82 | 2.82 |
| 1988 | 2.77 | 3.00 |
| 1989 | 3.22 | 3.23 |
| 1990 | 3.11 | 3.11 |
| 1991 | 3.18 | 5.68 |
| 1992 | 3.22 | 3.23 |
| 1993 | 3.09 | 3.09 |
| 1994 | 3.11 | 3.11 |
| 1995 | 2.84 | 3.62 |
| 1996 | 2.77 | 3.60 |
| 1997 | 2.27 | 3.62 |
| 1998 | 2.70 | 3.83 |
| 1999 | 3.28 | 4.15 |
| 2000 | 3.55 | 4.14 |
| 2001 | 4.30 | 4.26 |
| 2002 | 4.38 | 4.26 |
| 2003 | 3.47 | 3.47 |
| 2004 | 3.55 | 3.55 |
| 2005 | 4.85 | 5.59 |
| 2006 | 2.88 | 3.11 |
| 2007 | 2.75 | 2.63 |
| 2008 | 2.54 | 2.16 |
| 2009 | 1.80 | 1.78 |
| 2010 | .34 | .97 |
|
|
