U.S. innovation slowed this year for the first time in 13 years with a number of patent filings dropping 2.3% at the same time as U.S. patents issued to inventors and businesses in foreign nations jumped 6.3% for the year. At the same time the revenue of Patent Office dropped 200 million, which means a growing backlog of filings.

Currently, there are 740,000 patents pending, with an average wait time for approval of 40 months. The Patent Office isn't even able to look at applications for three years because of the backlog. That's an eternity for tech inventions, which tend to cycle through product generations in a year or so.

If backlog of 40 months is of no concern to the cutting edge innovators, perhaps the cost of filing and later on defending the patent is worth keeping up in mind.

The application, processing and legal fees average about $15,000 per patent, but the cost to defend those patents in court after they've been granted typically runs between $3 million to $6 million...