I have a 100m^2 raster of population and a series of buffers: 1,2,3,4,5,10,15,20,25,30,50 km. I am tasked with finding the population per buffer, which I am doing by using the "zonal statistics as table" geoprocess. The pixel value (population) sum decreases between 2km and 3km, and even further 3km to 4km. It then jumps way up to what I would expect to be normal at 5km. I have not gone beyond that because these results are unusable. I have verified that the projections between layers are consistent. I upgraded to the latest service pack and got identical results upon reprocessing. Can anyone help me out with this? This is a seemingly simple and straight-forward process. I've also verified that the scale is all positive (not centered on 0 which would allow negative numbers).