Show data table
| 1981 | 25.2B | 1997 | 30.4B | 2013 | 174B |
| 1982 | 21.6B | 1998 | 25.9B | 2014 | 163B |
| 1983 | 20.9B | 1999 | 30.1B | 2015 | 115B |
| 1984 | 21.7B | 2000 | 37.7B | 2016 | 109B |
| 1985 | 21.4B | 2001 | 34.9B | 2017 | 121B |
| 1986 | 17.9B | 2002 | 38.1B | 2018 | 139B |
| 1987 | 22.4B | 2003 | 47.9B | 2019 | 141B |
| 1988 | 20.7B | 2004 | 59.4B | 2020 | 111B |
| 1989 | 24.3B | 2005 | 80.8B | 2021 | 148B |
| 1990 | 18.2B | 2006 | 102B | 2022 | 184B |
| 1991 | 10.8B | 2007 | 115B | 2023 | 165B |
| 1992 | 19.9B | 2008 | 147B | 2024 | 161B |
| 1993 | 24B | 2009 | 106B | 2025 | 158B |
| 1994 | 24.9B | 2010 | 115B | 2026 | 173B |
| 1995 | 27.2B | 2011 | 154B | | |
| 1996 | 31.5B | 2012 | 174B | | |
Show data table
| 1981 | 7.04B | 1997 | 9.21B | 2013 | 49.4B |
| 1982 | 6.21B | 1998 | 7.91B | 2014 | 46.3B |
| 1983 | 6.08B | 1999 | 9.17B | 2015 | 34.5B |
| 1984 | 6.42B | 2000 | 11.6B | 2016 | 33.1B |
| 1985 | 6.45B | 2001 | 10.7B | 2017 | 36.6B |
| 1986 | 5.2B | 2002 | 11.6B | 2018 | 41.9B |
| 1987 | 6.23B | 2003 | 14.3B | 2019 | 42.8B |
| 1988 | 5.77B | 2004 | 17.5B | 2020 | 34B |
| 1989 | 7.14B | 2005 | 23.6B | 2021 | 44.7B |
| 1990 | 5.33B | 2006 | 29.5B | 2022 | 56.2B |
| 1991 | 3.13B | 2007 | 32.6B | 2023 | 50.8B |
| 1992 | 5.83B | 2008 | 39.6B | 2024 | 49.3B |
| 1993 | 7.23B | 2009 | 30.5B | 2025 | 48.4B |
| 1994 | 7.38B | 2010 | 33.1B | 2026 | 53B |
| 1995 | 8.11B | 2011 | 42.5B | | |
| 1996 | 9.43B | 2012 | 48.7B | | |
Show data table
| 1981 | 12.7B | 1997 | 19.8B | 2013 | 39.1B |
| 1982 | 11.5B | 1998 | 20.6B | 2014 | 39.3B |
| 1983 | 12.1B | 1999 | 20.2B | 2015 | 39.5B |
| 1984 | 12.7B | 2000 | 21.1B | 2016 | 40.7B |
| 1985 | 12.2B | 2001 | 21.2B | 2017 | 38.8B |
| 1986 | 13.2B | 2002 | 21.8B | 2018 | 39.8B |
| 1987 | 14.3B | 2003 | 25.6B | 2019 | 40.7B |
| 1988 | 12.9B | 2004 | 28.2B | 2020 | 38.8B |
| 1989 | 16.2B | 2005 | 31.2B | 2021 | 39.4B |
| 1990 | 12B | 2006 | 33.6B | 2022 | 42.1B |
| 1991 | 7.05B | 2007 | 35.6B | 2023 | 41.4B |
| 1992 | 12.9B | 2008 | 36.5B | 2024 | 40.8B |
| 1993 | 17.4B | 2009 | 33.9B | 2025 | 42.2B |
| 1994 | 18.9B | 2010 | 33.1B | 2026 | 42B |
| 1995 | 19.2B | 2011 | 36.3B | | |
| 1996 | 19.4B | 2012 | 38.7B | | |