What's the typical kickback percentage? (Duke charged 1%)

[Measure_for_Measure]

Prosecutors recommend that former Representative Duke Cunningham ® CA receive 10 years in jail on corruption charges. The AP story notes the existence of a “bribe memo”:

The prosecution’s sentencing memorandum included a copy of a “bribe menu” written under the Congressional seal on Cunningham’s office stationary. One column of figures represented the millions of dollars in contracts that could be “ordered” from Cunningham, according to prosecutors. The right column showed the amount of bribes Cunningham demanded in return.

According to the sentencing memorandum, Cunningham offered co-conspirator No. 2 – identified elsewhere as defense contractor Mitchell Wade – $16 million in contracts in exchange for a $140,000 bribe, which came in the form a 42-foot yacht, the Duke-Stir.

A copy of the relevant page of the sentencing memorandum is here. It shows some scrawlings that I’ve recalculated as follows:

Government Contract                     Bribe             Kickback Percentage
16 million                             $140,000                     0.875%
20 million                              340,000                     1.7%
25 million                              440,000                     1.76%  

My question is, “Was Cunningham undercharging?” My understanding is that far higher shares are paid in the third world, albeit to a larger number of corrupt officials. But that’s actually a pattern: for some reason bribes are both higher and more common in developing countries.

How do Cunningham’s percentages compare with those on, say, corrupt city contracts in the US or in other examples of malfeasance?

[Measure_for_Measure]

Those figures may be misleadingly narrow. Duke Cunningham confessed to accepting $2.4 million in bribes. I don’t have a good sense of the total value of the favors purchased.

Still, my question remains: what’s the typical kickback percentage at various locations and times?