|
| year | production | consumption |
| 1984 | | .28 |
| 1985 | .07 | .26 |
| 1986 | .09 | .37 |
| 1987 | .07 | .39 |
| 1988 | .11 | .37 |
| 1989 | | .42 |
| 1990 | .04 | .60 |
| 1991 | .02 | .21 |
| 1992 | | .19 |
| 1993 | | .12 |
| 1994 | .07 | .24 |
| 1995 | .04 | .13 |
| 1996 | .02 | .18 |
| 1997 | .02 | .20 |
| 1998 | .02 | .26 |
| 1999 | | .31 |
| 2000 | | .13 |
| 2001 | | .10 |
| 2002 | | .08 |
| 2003 | | .11 |
| 2004 | | .09 |
| 2005 | | .10 |
| 2006 | | .09 |
| 2007 | | .07 |
| 2008 | | .07 |
| 2009 | | .07 |
| 2010 | | |
|
|