Is it protestant tradition or current protestant population that affects corruption?

The percentage of Protestants 100 years ago has a more significant impact on today's level of corruption than the current percentage of Protestants within a country. This supports Williamson [Williamson, O.E., 2000. The new institutional economics: taking stock, looking ahead, Journal of Economic Literature XXXVIII, 595-613]'s claim that religion is at Level-1 of social analysis.