|
| year | production | consumption |
| 1980 | .45 | 527.00 |
| 1981 | .11 | 471.00 |
| 1982 | .25 | 402.00 |
| 1983 | .42 | 365.00 |
| 1984 | .24 | 346.00 |
| 1985 | .15 | 357.00 |
| 1986 | .07 | 371.00 |
| 1987 | .07 | 364.00 |
| 1988 | .05 | 350.00 |
| 1989 | .05 | 336.00 |
| 1990 | .05 | 336.00 |
| 1991 | .04 | 339.00 |
| 1992 | .02 | 371.00 |
| 1993 | .01 | 365.00 |
| 1994 | .08 | 390.00 |
| 1995 | .08 | 388.00 |
| 1996 | | 412.00 |
| 1997 | | 391.00 |
| 1998 | | 401.00 |
| 1999 | | 394.00 |
| 2000 | | 361.99 |
| 2001 | | 369.00 |
| 2002 | | 372.59 |
| 2003 | | 369.01 |
| 2004 | | 368.39 |
| 2005 | | 359.57 |
| 2006 | | 354.47 |
| 2007 | | 350.37 |
| 2008 | | 336.81 |
| 2009 | | 318.28 |
| 2010 | | 335.60 |
| 2011 | | 316.05 |
|
|