Keeping score

Since last January, I've been keeping track of the number of movies I watch every year in the sidebar. The problem with this system is, what do I do with partial movies? For instance, last year I watched about two-thirds of both Cloverfield and Great Expectations; in both cases, enough of the movie that I felt like I'd invested a significant amount of time in seeing them, but in neither case had I watched the whole movie.

This has come up again because the other week I watched the remake of The Omen, but got thoroughly fed up by the time I got to the scene where Damien murders his mother, and I'm not sure whether to count it as half a movie or just ignore it.