Greed has no limit
Yes, in every country we can find corrupt officials.
In my opinion if the official have been motivated by instinct and urge to acquire power and rule over people such person will tend to be corrupt, regardless of the salary that is receiving.
There is sadly no "crash course" on how to become ethical official. I wish there would be. The motivation shall be the greater good for people, and not personal gains.
I just guess that buddhist monks could make good officials. Something like Dalai Lama.