I read somewhere that the cost of government activity, on any program, is 38%
But, I can definitively tell you this - when bidding for government contracts, we used to figure out what it cost to build the item/service, and then add 46% 'wrap rate' to cover the additional costs of managing and responding to government oversight.
In short, we raised the cost of production 46% because it was a government contract. And, before you ask, our average profit margin (which is predefined in the contract) was 7%.
Let me clarify this .... if an item costs $1 to build (including profit), we would have to charge the government $1.46 because of the effort necessary to handle their oversight. In addition, the taxpayer would pay an extra 38% labor for the government's effort - raising the total item cost to $1.93. Now you know why we have $600 toilet seats and $300 hammers.