|
| year | production | consumption |
| 1980 | | 17.40 |
| 1981 | | 16.80 |
| 1982 | | 17.30 |
| 1983 | | 16.40 |
| 1984 | | 19.50 |
| 1985 | | 19.20 |
| 1986 | | 19.63 |
| 1987 | | 19.22 |
| 1988 | | 16.32 |
| 1989 | | 17.01 |
| 1990 | | 16.90 |
| 1991 | | 15.66 |
| 1992 | | 19.09 |
| 1993 | | 19.45 |
| 1994 | | 23.48 |
| 1995 | | 25.26 |
| 1996 | | 25.19 |
| 1997 | | 23.50 |
| 1998 | | 25.17 |
| 1999 | | 27.78 |
| 2000 | | 29.55 |
| 2001 | | 29.44 |
| 2002 | | 30.05 |
| 2003 | | 30.32 |
| 2004 | | 33.85 |
| 2005 | | 36.18 |
| 2006 | | 37.15 |
| 2007 | | 37.68 |
| 2008 | | 26.07 |
| 2009 | | 36.16 |
| 2010 | | 36.65 |
| 2011 | | 43.00 |
|
|