Is electronic commerce software patentable?

Dennis Crouch published a great post on his blog about the allowance of US patent applications in various technology area here.

The allowance rate for 2014 was between 59% and 75% across the technology areas, except electronic commerce that had an allowance rate of less than 10%.

From this data, it appears that electronic commerce software is hard to protect with a patent, however I do not have enough information about the data to be sure.