Why is there no Z spam?

I get a lot of spam. In 2005, I got just under half a million pieces of it myself at my work email account. So I would like to think I am familiar with it. Each morning I download my 500 or so pieces of the stuff that have built up since the time I left work the night before. Each morning, it all gets routed to the junk mail folder like it always does.

I usually take a quick scan through the folder to see if anything shouldn't be there. I usually sort by subject; that seems to help me weed out things that shouldnt' be there faster. But this morning something occurred to me. Inbetween the spams that start with the letter "Y", and the spams that start with gibberish in the subject, there's no love for the letter "Z".

It appears that I rarely get any spam that starts with the letter "Z". Why is that? Doesn't anyone love "Z"? Come on, "Z" needs some love!