Re: Shortage ?
You can count the number of tech jobs in the United States, but how could you count jobs that do not currently exist, such as "Secretary of the second personal Assistant to Mr. Kieren" or "President's tweet speech writer" or "Manager of the Antarctica division of the refrigerator business unit"?
What you can count, however, is the number of IT specialists which currently are not needed by the industry. Or maybe you can take the total annual profit and divide it by the average tech salary to get the number of jobs that the sector could create if it were so inclined.
A good measure would be the number of bugs and exploits that lie unfixed and undiscovered in today's software, a.k.a. the nation's Technical Debt.