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
| Datum | Wert | Ändern , % |
|---|---|---|
| 2021 | 19 | 4,98 % |
| 2020 | 18 | -7,25 % |
| 2019 | 20 | -2,95 % |
| 2018 | 21 | -3,12 % |
| 2017 | 21 | -3,54 % |
| 2016 | 22 | 29,29 % |
| 2015 | 17 | -2,18 % |
| 2014 | 17 | -17,77 % |
| 2013 | 21 | 37,39 % |
| 2012 | 15 | -4,09 % |
| 2011 | 16 | 3,06 % |
| 2010 | 16 |