Avis - Avis First: How is a qualification 'year' calculated?

Was surprised this morning by an Avis First welcome packet sitting on my chair at work. I knew I'd come CLOSE in 2011 (I think I was one rental and a handful of days short), so I was wondering - how is Avis calculating the eligibility year? Is it a calendar year or a consecutive 12-month period? (A week-long rental at the beginning of this month would have put me over the top if they're using 12 consecutive months as the qualification 'year'.)

As I'm new to First, I'm wondering what to expect from a practical standpoint. I know upgrades are 'standard', but am I going to spend a lot of time declining an 'upgrade' into an OMC (like a Grand Marquis), or can I expect something more genuine, like a Caddy/BMW or a hybrid/'cool car'?

From a Googled Avis First web page:

You've completed at least 12 qualifying rentals, or 35 or more qualifying rental days, on one Wizard number, in a calendar year.

You've made sure that all qualifying rentals have checked in and checked out in the same calendar year.

I'm forever being "upgraded" to a Grand Marquis or Crown Victoria, both which I always turn down. I try to get any Ford car I can, and twice I've been upgraded to a Ford Mustang, one of which was a 5.2l G/T, a real beast of car and a lot of fun to drive. Never had a Camaro, BMW or any such type. Am an Avis First member but don't beleive I get any tangible benefits on top of Preferred members get.

I'm forever being "upgraded" to a Grand Marquis or Crown Victoria, both which I always turn down. I try to get any Ford car I can, and twice I've been upgraded to a Ford Mustang, one of which was a 5.2l G/T, a real beast of car and a lot of fun to drive. Never had a Camaro, BMW or any such type. Am an Avis First member but don't beleive I get any tangible benefits on top of Preferred members get.
Ah. So more of the same with a slightly fancier card. Got it.

If it makes you feel any better, I usually insist on a Ford product as well, if it can be helped. My personal car ('11 Fiesta SES) came with 3 years of SYNC Traffic & Directions, and I can use that in any other SYNC-equipped car, since the account is tied to my phone number and not to the specific vehicle. Saves me a bunch on GPS rental.

I've been Avis first since mid last summer and I'm consistently upgraded more than 1 or two car classes. Other than that I don't see any real benefit except the free days. With the frequency that I now rent (2-3weeks/month), I generally take advantage of upgrades. Since becoming first I've had a Camaro SS Conv, Ford Mustang, Cadillac SRX, Chrysler 300, Buick Lacrosse, and the Infinity M37 (currently) to name a few. A few of these I have asked for specifically and been given for the same intermediate rate I reserved under.

In addition to being First/Preferred, Avis has a back-end thing called "High Volume Renter." I'm not sure of their requirements for this (maybe 100 or 150+ days/year; EZMonee spelled it out a few years ago), but if this applies to you, your profile will be denoted with HVR or something similar for agents to see. They are *supposed to* upgrade you, if possible, since you're a loyal renter in their eyes. In my opinion, they should make this "elite category" public knowledge, but they feel differently.