st: weighted population size smaller than sample size?

["Akresh, Ilana Redstone" <redstone@illinois.edu>]

I am using Stata 9 and have svyset my data with a pweight. The number of observations is 8572. When I run a weighted mean (svy: mean x) I get a population size that is smaller than the sample size (population size = 8545). How is this possible? Is there something wrong with the weight or with how I have svyset the data or something else?


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