declining oil revenue and a further cut in corporate income tax rates constrained revenue collection for southeast asia total tax revenues as a share of gdp ranged between in indonesia and in thailand in while the optimum taxtogdp ratio would depend on a number of factors such as a country s preference for public goods the availability of nontax revenues and the structural characteristics of the economy by all accounts there seems to be room for increasing tax revenues in a number of countries for instance it was found in a study that indonesia s potential taxtogdp ratio is approximately percentage points higher than the actual level escap a