Google External Keyword tool confusion

Can anyone explain how in the google adwords keyword tool, in exact match, a phrase may have in the hundreds of thousands "average" monthly searches, yet the data from the most recent month is "not available". By my reading if no data is available then we're to believe its getting less that 100 searches a month. We're are supposed to believe it averages 100,000 a month but in America/English for last month less than 100?

I find that hard to believe, anyone shed some light?

None in particualar, I have a mini site formula I was using to choose domains. Research a keyword in the tool then sory by global monthly, with the "exact" chosen from the drop down. Then work my way down checking for available domains with the exact terms. Iv found a lot of good keywords with in the HUNDREDS of thousands global, yet for local december I get not enough data. I checked the adwords help site, and various forms and supposidly not enough data available = less then 100.

How can something be being searched for 100,000 times on average in the last 12 months, but localy only 100. Especially when most the stuff I look up is US based.

(i.e. US tv shows)

That's not the only thing I have seen. I've seen phrase matches rank higher than broad matches. I don't know what to believe half the time when it comes to the number of searches it says.