Right now, there seems to be no definition of what the dates mean on copyright / phonographic copyright rels. In a lot of cases I've seen, they seem to be used with the start date of whatever is printed and an open end date, I assume to represent that it's not just they had the copyright for that one year. That kinda breaks for cases like "(P) 2000 - 2001" though, unless we should be doing "2000 - ". We should probably decide how this should be dealt with. For an example, see https://musicbrainz.org/label/0239ec2c-e162-4dab-a3a3-e502a6284a9e/relationships