I see your on Lion, from your profile and someone answered above. But in case someone else reads this who is using SL, you have to update manually from:
iWork 9.1 was the last version that will work on SL, assuming you installed from the cd retail box. Apple, since moving to Mac App Store versions, turned off the software update availablility.
iwork 9.1 was the last that SL will take. I had to go through apple support to figure this out as my retail version was iWork 903 and software update would not find anything newer (and I did have the apps in the right location within the Applications Folder). I checked multiple macs to make sure I was seeing this same behavior before calling apple support. They confirmed you had to run updates manually.
After the above link, you also have to update to Keynote 5.1.1 manually as well.
Oddly enough, If I would have installed iWork retail cd onto Lion, apparently SU would have registered an update then.