You need pages 10 and 11. Besides, that's an outdated source.
http://arxiv.org/abs/0903.0676
increases the limit on the observed partial mean life via p \rightarrow e^+ \pi^0 channel (the one predicted by common GUTs) by a factor of 5, to 8.8 x 10^{33} years.
The original non-supersymmetric SU(5) prediction was, I think, somewhere around 10^{30} years, and that has been ruled out.
However, mean life is extremely sensitive to the structure of the unified theory. It scales roughly as the fourth power of the unification energy (or, more accurately, as the fourth power of mass of the massive boson responsible for the decay, which is probably near unification energy). We already know that naive (minimal) non-supersymmetric SU(5) does not result in clean unification, because all three coupling constants fail to meet at the same point. If we allow additional particles beyond those needed to construct minimal SU(5), all hell breaks loose, the unification energy can be anywhere below Planck mass, and proton lifetime can potentially be as high as 10^{42} years.
That is, in fact, the way SUSY GUTs "deal" with the problem - contributions from superparticles distort running couplings just enough to raise the unification energy by a couple of orders of magnitude, and lifetime becomes high enough to agree with observations. But that approach is by no means exclusive to SUSY.
