So I looked, starting at fhi.no, and found quickly found several studies that use data based on either the Norwegian cancer registry, the cause-of-death registr

So I looked, starting at fhi.no, and found quickly found several studies that use data based on either the Norwegian cancer registry, the cause-of-death registry or both. These aren't samples. The cause of death registry includes all deaths and the cancer registry includes everyone who's been diagnosed with cancer, even people who received no treatment. This means that studies that investigate e.g. cancer caused by smoking and use these data sources are nationwide rather than sampled.