|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 2.88 | 5.44 |
| 1987 | 2.96 | 6.08 |
| 1988 | 3.01 | 6.59 |
| 1989 | 3.15 | 6.78 |
| 1990 | 2.42 | 7.33 |
| 1991 | 3.13 | 6.64 |
| 1992 | 2.73 | 8.16 |
| 1993 | 2.83 | 9.11 |
| 1994 | 2.94 | 9.53 |
| 1995 | 2.65 | 8.59 |
| 1996 | 3.09 | 12.67 |
| 1997 | 3.20 | 13.11 |
| 1998 | 2.87 | 15.03 |
| 1999 | 3.27 | 15.87 |
| 2000 | 3.47 | 17.52 |
| 2001 | 3.43 | 18.70 |
| 2002 | 2.59 | 18.86 |
| 2003 | | 18.42 |
| 2004 | | 18.97 |
| 2005 | .02 | 19.28 |
| 2006 | .02 | 20.04 |
| 2007 | | 21.06 |
| 2008 | | 20.59 |
| 2009 | | 22.81 |
| 2010 | | 22.41 |
|
|