well, i contacted a few rescues, they all said the same thing. i won't find a chart b/c there is such a size variation within the breed.
PB's do grow very quickly, though, BUT they stop growing at a fairly early age, where giant breeds (like danes, saints) grow for several years. with the way your baby is growing, i would seriously look into what you're feeding. some dog foods can cause puppies to grow entirely too fast, causing bone and joint problems, which are not only painful for them, but even more painful to have to watch your baby go though.