powertop statistics display zero

I installed powertop to find out information about my laptop's power consumption.

Unfortunately it does not display some of the essential statistics, they remain at zero. For example the first line of the "Overview" screen:

Summary: 0.0 wakeups/second, 0.0 GPU ops/second and 0.0 VFS ops/sec

All of them stay at 0.0. Also the "Events/s" column stays at 0.0 for all rows below.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: powertop 1.97-2
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Uname: Linux 3.0.0-12-generic x86_64
ApportVersion: 1.23-0ubuntu3
Architecture: amd64
Date: Thu Oct 13 20:44:01 2011
InstallationMedia: Xubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110920.2)
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: powertop
UpgradeStatus: No upgrade log present (probably fresh install)