According to Doctors Without Borders, the number is much larger. I don't recall the exact numbers, but I believe the government places the total number of fatalities since the beginning of the global war on terror somewhere in the hundreds of thousands, while the actual number is in around five million... But then the government has never seemed to be all that great with numbers.
Drone strikes have been known to cause more collateral damage as of the latest strikes on record. However, can the statistics reported post-op be completely veritable? Of course, for public relations purposes, our forces have to remain within the positive media light; so it might not be as farfetched to believe that they are reporting "justifieable" numbers to measure collateral damage.
It it quite possible that the government is playing down the number of drone strike casualties. As seen by Snowden and Wikileaks, there has been many government lies and cover ups. I have heard of more cases than this. Usually when the truth comes out the government pays someone off not to sue.