|
| year | production | consumption |
| 1980 | .35 | .35 |
| 1981 | .35 | .35 |
| 1982 | .35 | .35 |
| 1983 | .40 | .40 |
| 1984 | .40 | .40 |
| 1985 | .40 | .40 |
| 1986 | .40 | .40 |
| 1987 | .30 | .35 |
| 1988 | .93 | .93 |
| 1989 | | |
| 1990 | | |
| 1991 | .80 | .80 |
| 1992 | .77 | .77 |
| 1993 | 1.07 | 1.07 |
| 1994 | .78 | .78 |
| 1995 | .93 | .93 |
| 1996 | 1.03 | 1.03 |
| 1997 | 1.03 | 1.03 |
| 1998 | 1.03 | 1.03 |
| 1999 | 1.03 | 1.03 |
| 2000 | 1.03 | 1.03 |
| 2001 | 1.03 | 1.03 |
| 2002 | 1.03 | 1.03 |
| 2003 | 1.03 | 1.03 |
| 2004 | 1.03 | 1.03 |
| 2005 | 1.03 | 1.03 |
| 2006 | 1.03 | 1.03 |
| 2007 | .99 | .99 |
| 2008 | 1.13 | 1.13 |
| 2009 | .71 | .71 |
| 2010 | .71 | .71 |
| 2011 | | |
|
|