|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | | .30 |
| 1987 | | .30 |
| 1988 | | 1.82 |
| 1989 | | 2.37 |
| 1990 | 2.11 | 2.48 |
| 1991 | .97 | 1.92 |
| 1992 | 1.38 | 1.90 |
| 1993 | 1.38 | 1.79 |
| 1994 | | 1.92 |
| 1995 | | 2.54 |
| 1996 | | 1.91 |
| 1997 | | 2.59 |
| 1998 | | 2.59 |
| 1999 | | 2.59 |
| 2000 | 21.19 | 2.58 |
| 2001 | 21.25 | 2.59 |
| 2002 | 21.25 | 2.59 |
| 2003 | 21.25 | 2.66 |
| 2004 | 21.19 | 2.66 |
| 2005 | 21.21 | 2.65 |
| 2006 | 23.62 | 2.86 |
| 2007 | | 2.72 |
| 2008 | | 2.72 |
| 2009 | | 2.73 |
| 2010 | | 2.73 |
|
|