Q: I read your article suggesting that U.S. house foreclosures could reach 4 million in 2010.

Can you tell me the total number of owned housing units in the U.S.? Without a denominator, the housing foreclosure number is a little difficult to grasp. Most articles I see mention the percent change in foreclosures, say 3 million to 3.5 million, but without knowing the total number of houses, I’m not sure how big the problem actually is.

A: Great question. You’re right – the numbers are so big, it’s hard to get your mind around them.

Here are some numbers to help you put things into perspective: There are about 110 million households (give or take a few million). About 65 percent of American households own their own home, according to the Census bureau. So, we’re talking about roughly 65 million to 70 million homeowners.

Of those, we’ve had 4 to 5 million foreclosures and economists from the National Association of Realtors and the National Association of Home Builders estimate that we’ll have another 4 to 12 million additional foreclosures before we get the U.S. housing market back on track.

So, when all is said and done, we’ll have had somewhere between 8 and 17 million foreclosures out of 68 million homeowners.

It’s a pretty big number.

Historically, about 2 percent of homeowners defaulted on their mortgage, and those homeowners who actually were foreclosed on and had to leave their homes was a tiny percent of that.

The foreclosure numbers going forward don’t look good, whether you look at the picture of people losing their homes or look at the overall picture of homeowners and the people affected by the housing crisis.