W A T S A F E r , s s = u n i m p r o v e d = 1.4998 − 1.4532 ∗ l n ( G D P P C P r ) − 0.5593 ∗ l n ( E D Y R S A G 25 r ) {\displaystyle WATSAFE{r,ss=unimproved}=1.4998-1.4532*ln(GDPPCP_{r})-0.5593*ln(EDYRSAG25_{r})}
