Hi Rory,
as soon as you install a new Debian release, users will be asked if they like to participate in Debian’s popularity-contest (popcon). By default this option is set to no because of privacy reasons. The current popcon values for openrefine are available here. As you can see there are currently 36 reported installations of openrefine. So what does it mean? Compared to coreutils, an essential Debian package, the number is small because coreutils is installed on every Debian system while openrefine is only optional. In comparison to tomcat11, a popular Java package, the number is reasonable. Since the release of Debian 13 both packages appeared to attract roughly the same number of new users. There are several drawbacks to popcon though. First of all I compare two completely different packages, one targeted for headless servers, the other one for single-user desktop environments. It is unlikely both are installed on the same system but we don’t have any data to confirm or deny that. Popcon also doesn’t include installations from all of Debian’s 100+ derivatives, only a few smaller ones. The larger ones like Ubuntu or Mint are not included but many desktop users use them. So in short you have to take these information with a grain of salt. Usually the numbers ramp up after a package was included in several stable releases because most Debian users prefer stable and you can see an uptrend since the release of Debian 13 last year.
I should also note that the introduction of openrefine required new Java libraries or tools for Debian which may also have a distinct user base or will be used by other people for different software projects now or in the future. I don’t have any exact numbers though.
Maybe you could promote the Debian package a little if you put a notice or link on the download page?