Figures in constant (2020) US$ are present according to calendar year, calculated on the assumption that, where financial years do not correspond to calendar years, spending is distributed evenly through the year
| التاريخ | Value | تغيير , % |
|---|---|---|
| 2021 | 22,501 | 3.14 % |
| 2020 | 21,817 | 4.14 % |
| 2019 | 20,948 | 0.60 % |
| 2018 | 20,822 | 1.22 % |
| 2017 | 20,572 | 4.28 % |
| 2016 | 19,728 | 5.29 % |
| 2015 | 18,736 | 1.43 % |
| 2014 | 18,471 | 7.65 % |
| 2013 | 17,158 | 3.12 % |
| 2012 | 16,640 | 1.92 % |
| 2011 | 16,327 | 0.66 % |
| 2010 | 16,219 |