|
| year | production | consumption |
| 1980 | | 6.70 |
| 1981 | | |
| 1982 | | 7.10 |
| 1983 | | 7.50 |
| 1984 | | 7.20 |
| 1985 | | 7.95 |
| 1986 | | 8.42 |
| 1987 | 1.36 | 7.99 |
| 1988 | 1.29 | 7.24 |
| 1989 | 1.10 | 7.85 |
| 1990 | 1.25 | 8.16 |
| 1991 | 1.20 | 8.34 |
| 1992 | 1.36 | 8.44 |
| 1993 | 1.27 | 8.40 |
| 1994 | 1.23 | 8.14 |
| 1995 | 1.30 | 8.21 |
| 1996 | | 7.92 |
| 1997 | .90 | 9.19 |
| 1998 | 1.60 | 9.49 |
| 1999 | 1.94 | 9.74 |
| 2000 | 1.53 | 10.82 |
| 2001 | 1.27 | 10.37 |
| 2002 | | 10.37 |
| 2003 | | 10.57 |
| 2004 | | 7.10 |
| 2005 | | 9.83 |
| 2006 | 1.03 | 9.30 |
| 2007 | 1.11 | 8.30 |
| 2008 | 1.10 | 7.72 |
| 2009 | .77 | 9.30 |
| 2010 | | 8.78 |
| 2011 | | |
|
|