The paperclay and subsequent technical infomation provided here is manufactured by IMCO in Sacramento. It's a proprietary blend and is carried locally here in So. Calif by Aardvark Clay Company in Santa Ana, in 25lbs bag.
The information provided here is from my own experience.
From green to bone dry - 5 %
After bisque - not measured
After high fire (Cone 10 reduction) - 10%
Total shrinkage is around 15%
Considering other traditional clay bodies (total shrinkage ) is anywhere from 8% (low end) to 12-13%(high end), this paperclay shrinkage is quite a bit. It's good to know so you can compensate by making your pieces a bit larger than you normally would.