|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 1.75 | 5.41 |
| 1987 | 2.25 | 6.93 |
| 1988 | 1.85 | 6.51 |
| 1989 | 1.67 | 8.90 |
| 1990 | 2.72 | 7.92 |
| 1991 | 2.46 | 7.43 |
| 1992 | 2.82 | 9.15 |
| 1993 | 2.33 | 8.89 |
| 1994 | 2.52 | 10.18 |
| 1995 | 1.81 | 14.17 |
| 1996 | 1.44 | 11.85 |
| 1997 | 1.15 | 13.31 |
| 1998 | 1.23 | 15.23 |
| 1999 | 1.15 | 17.62 |
| 2000 | .97 | 15.17 |
| 2001 | 1.06 | 13.73 |
| 2002 | .94 | 17.05 |
| 2003 | .82 | 18.17 |
| 2004 | .67 | 18.49 |
| 2005 | .53 | 16.80 |
| 2006 | | 17.23 |
| 2007 | | 18.39 |
| 2008 | | 18.70 |
| 2009 | | 19.44 |
| 2010 | | 19.19 |
|
|