Unfortunately, we cannot give an apples-to-apples comparison on the districts from the 2010 data because there have been changes in the way the underlying data has been formatted by the Census Bureau. The most noteworthy of those changes is that we now have an additional three Census Designated Places (CDPs) (Mt. Bullion, Yosemite West, and Crane Creek [Foresta]). Unfortunately, the boundaries of many of the existing Census Designated Places also changed, with some getting smaller while others got larger. In addition, a lot of the CDPs and census blocks also changed in size or shape. Since the population numbers are attached to a census block, it is necessary for the entire census block to be within a district in order for the count to be accurate (because we are legally charged with using only the data from the census, and it does not break the data to a smaller level.) In short, the new census block shapes and CDP boundaries are not an exact match for those previously used which prevents exact comparisons.
However, while we cannot look to the overall district totals, what we are using as a measure of the change are the CDP numbers, which are the population clusters within the County. Please see the spreadsheet of CDP data sorted by district, which shows that District 1 CDPs have lost the most population, followed by District 4 and, to a lesser degree, District 5; while Districts 3 and 2 show increases in their population clusters. This data also shows that the Census Bureau has also downsized District 1 CDPs pretty significantly, as well, with Midpines being the most notable.