Pleased, because it confirms that they're steady sellers on a "few copies a month" basis which is bringing in a small but useful income over the course of a year. I knew that anyway from the last sales figures, but confirmation is always nice.
Appalled, because this suggests that a lot of other products which I would tend to think of as much stronger sellers must be doing worse.
On the whole I suspect that it's just a statistical blip, maybe there just haven't been many strong new releases in the last month, or possibly the result of a review I haven't seen. Whatever, it's nice to see them back there again.