I would make a couple of points on surveys.
Surveys are very important as part of the overall information system and provide us with accurate data. Again, surveys depend on the census in order to make sure they're accurate. However, surveys can't provide data for small areas. For example, a survey won't provide data for your constituencies. You need something like a census, which profiles your constituencies once every five years in much detail. Or a survey won't provide data for small groups, particularly in small areas. So surveys and a census are certainly complementary, but they do not replace one another.