|
| year | production | consumption |
| 1980 | 2.47 | 2.47 |
| 1981 | 3.18 | 3.18 |
| 1982 | | |
| 1983 | 3.20 | 3.20 |
| 1984 | | |
| 1985 | | |
| 1986 | | |
| 1987 | 2.10 | 2.10 |
| 1988 | 2.12 | 2.12 |
| 1989 | 2.12 | 2.12 |
| 1990 | | |
| 1991 | 1.37 | 1.37 |
| 1992 | .85 | .85 |
| 1993 | 1.06 | 1.06 |
| 1994 | 1.06 | 1.06 |
| 1995 | .71 | .71 |
| 1996 | .71 | .71 |
| 1997 | 1.77 | 1.77 |
| 1998 | 1.77 | 1.77 |
| 1999 | 1.77 | 1.77 |
| 2000 | 1.77 | 1.77 |
| 2001 | 1.77 | 1.77 |
| 2002 | 1.77 | 1.77 |
| 2003 | 1.77 | 1.77 |
| 2004 | 1.77 | 1.77 |
| 2005 | 1.77 | 1.77 |
| 2006 | 2.12 | 2.12 |
| 2007 | 1.27 | 1.27 |
| 2008 | 2.12 | 19.78 |
| 2009 | 2.12 | 19.78 |
| 2010 | 2.12 | 19.78 |
| 2011 | 2.12 | 7.42 |
|
|