Well, it must've been purposely limited availability then.
Probably reducing numbers each year, because less people buy calendars each year, or wait to get them in the January clearance sales.
Here in the Britain, Amazon aren't stocking it no more (besides acknowledging the ISBN, I'm not sure they ever did actually) ... No regular Star Trek SOTL in sight, or I'd have bought it... as I've done for years.
Well, Australian calendar distributors dropped all "Star Trek" calendars from their annual range in about 2006 (with the 2009 movie a notable exception), so they are rarely seen in bricks and mortar stores, so I buy imported ones from my local science fiction specialist bookshop, or sometimes Amazon US if they fail to order a particular title.
Trawl eBay. Old ST calendars are often available for a few cents.