Using current USB block erupter group buy price to determine ROI

[dwdoc]

Determine the current btc group buy price of an ASICminer USB block erupter (P), for example here:

https://bitcointalk.org/index.php?topic=270999.0

The estimated 12 month ROI for any device with a GH/s rate of G:

G/(P x 3.45) = 12 month ROI

For example for the KNCminer Jupiter (if it started hashing now):

400/(.33 x 3.45) = 351btc