For years, we’ve been asked how many video rental stores there are in the U.S. And for a good number of years, we haven’t had a spot-on answer—usually something like "around 20,000" (voice going up in a sing-song question at the end).

Turns out, according to our friends and research partners at Rentrak, that was pretty close to right—up to a point.

According to Rentrak, there were 21,157 bricks-and-mortar rental stores in the U.S., including chains, independents and supermarkets, until 2006.

By 2008, however, that number had shrunk to just 14,235, Rentrak says, as the result of pretty massive closures at Blockbuster (600+ stores closed), Movie Gallery/Hollywood (1,600+ stores closed across the two brands) and indies and supermarkets (more than 4,000 locations closed).

That’s a total reduction in the bricks-and-mortar footprint by 33%.

As a result, Rentrak has revamped its model for estimating U.S. rental revenue, as reflected in our page 1 story on the first-quarter home entertainment market.

Under the new model, Rentrak puts the rental market for first-quarter 2009 at $1.69 billion, just about even with its revised revenue for 2008, of $1.67 billion.

Rentrak’s previous model showed first-quarter 2008 revenue closer to $2 billion, on the assumption that there were more stores operating at that time than there actually were.

The growth trend of +1% is good news, driven by kiosk rentals and Blu-ray Disc rentals, both of which have doubled year-to-year, according to Rentrak.

Of course, it’s a slight gain on a market that’s smaller than it was previously thought to be. You can believe that sent a number of studio execs scrambling to analyze the new Rentrak model last week.

For the rental market, as for so many other consumer goods and services, there is a new reality. It includes fewer traditional stores and per-transaction rentals, more kiosks charging $1 per night and more subscription plans.