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 , % |
|---|---|---|
| 1992 | 7,006 | 1.44 % |
| 1991 | 6,907 | -34.41 % |
| 1990 | 10,530 | -12.76 % |
| 1989 | 12,071 | 47.69 % |
| 1988 | 8,173 | 2.39 % |
| 1987 | 7,982 | 0.59 % |
| 1986 | 7,935 | -0.83 % |
| 1985 | 8,001 | 5.62 % |
| 1984 | 7,575 | 2.99 % |
| 1983 | 7,355 | 1.83 % |
| 1982 | 7,223 | 1.27 % |
| 1981 | 7,133 |