Show data table
| 1980 | 3.91B | 1996 | 9.59B | 2012 | 21.4B |
| 1981 | 3.45B | 1997 | 10.2B | 2013 | 22B |
| 1982 | 3.41B | 1998 | 10.9B | 2014 | 22.6B |
| 1983 | 3.26B | 1999 | 11.3B | 2015 | 23.4B |
| 1984 | 2.39B | 2000 | 11.8B | 2016 | 24.2B |
| 1985 | 2.32B | 2001 | 12.3B | 2017 | 25B |
| 1986 | 2.33B | 2002 | 12.7B | 2018 | 26B |
| 1987 | 2.37B | 2003 | 13.2B | 2019 | 26.9B |
| 1988 | 2.77B | 2004 | 13.7B | 2020 | 24.9B |
| 1989 | 3.17B | 2005 | 14.7B | 2021 | 29B |
| 1990 | 4.82B | 2006 | 16B | 2022 | 31.9B |
| 1991 | 5.25B | 2007 | 17B | 2023 | 33.9B |
| 1992 | 5.81B | 2008 | 18B | 2024 | 35.4B |
| 1993 | 6.68B | 2009 | 17.6B | 2025 | 37.3B |
| 1994 | 7.68B | 2010 | 18.4B | 2026 | 39.8B |
| 1995 | 8.92B | 2011 | 20.3B | | |
Show data table
| 1980 | 3.91B | 1996 | 9.59B | 2012 | 21.4B |
| 1981 | 3.45B | 1997 | 10.2B | 2013 | 22B |
| 1982 | 3.41B | 1998 | 10.9B | 2014 | 22.6B |
| 1983 | 3.26B | 1999 | 11.3B | 2015 | 23.4B |
| 1984 | 2.39B | 2000 | 11.8B | 2016 | 24.2B |
| 1985 | 2.32B | 2001 | 12.3B | 2017 | 25B |
| 1986 | 2.33B | 2002 | 12.7B | 2018 | 26B |
| 1987 | 2.37B | 2003 | 13.2B | 2019 | 26.9B |
| 1988 | 2.77B | 2004 | 13.7B | 2020 | 24.9B |
| 1989 | 3.17B | 2005 | 14.7B | 2021 | 29B |
| 1990 | 4.82B | 2006 | 16B | 2022 | 31.9B |
| 1991 | 5.25B | 2007 | 17B | 2023 | 33.9B |
| 1992 | 5.81B | 2008 | 18B | 2024 | 35.4B |
| 1993 | 6.68B | 2009 | 17.6B | 2025 | 37.3B |
| 1994 | 7.68B | 2010 | 18.4B | 2026 | 39.8B |
| 1995 | 8.92B | 2011 | 20.3B | | |
Show data table
| 1980 | 12.4B | 1996 | 15.9B | 2012 | 21.7B |
| 1981 | 11.7B | 1997 | 16.4B | 2013 | 22.2B |
| 1982 | 10.9B | 1998 | 16.8B | 2014 | 22.6B |
| 1983 | 11.1B | 1999 | 17.2B | 2015 | 23.1B |
| 1984 | 11.2B | 2000 | 17.4B | 2016 | 23.7B |
| 1985 | 11.3B | 2001 | 17.5B | 2017 | 24.3B |
| 1986 | 11.3B | 2002 | 17.8B | 2018 | 24.8B |
| 1987 | 11.6B | 2003 | 18.1B | 2019 | 25.4B |
| 1988 | 11.8B | 2004 | 18.3B | 2020 | 23.4B |
| 1989 | 11.9B | 2005 | 18.8B | 2021 | 26.2B |
| 1990 | 12.5B | 2006 | 19.6B | 2022 | 27B |
| 1991 | 12.7B | 2007 | 19.9B | 2023 | 28B |
| 1992 | 13.6B | 2008 | 20.4B | 2024 | 28.7B |
| 1993 | 14.4B | 2009 | 19.9B | 2025 | 29.7B |
| 1994 | 15.1B | 2010 | 20.4B | 2026 | 30.7B |
| 1995 | 15.8B | 2011 | 21.1B | | |