@bythewell - Unfortunately, in many cases the people who are corrupt are just trying to feed their families as well.
Corruption at the higher levels should be weeded out first, so that money will trickle down and make it easier to tell lower level people they can't commit corrupt actions either.
For example, corruption isn't always bribes. Sometimes it takes the form of nepotism, or favoring your family and friends. In a country that is very poor, how could you not favor your friends and family though?
If you giving them a job, or first crack at the new stock, or a passport means the difference between life or death for them, how can you expect an ordinary person to make that choice?
On the other hand, corrupt rich people, who are just trying to get richer, should be stopped for the good of everyone.