Estimating sugar & cream for a coffee service I'm helping to organize a workshop, and we're planning on providing coffee ... but not being in the catering business (nor a coffee drinker), I really have no idea how to estimate these things.

I found on Giant Food's catering tips page, the following recommendations:


Plan on guests consuming a cup of coffee every 1.3 hours (3 drinks over 4 hours).
Coffee consumption peaks in the morning, late afternoons and after meals; coffee drinkers will usually consume 1½ cups each.
Don't forget cream and sugar and sugar substitutes!


I've also found an estimate of breakdown of caff/decaf/tea if male or female groups, and I've misplaced the link, but I had previously found a site talking about how the length of the breaks can affect how much coffee people consume (if they have 30 min, they have time to drink &amp; get a refill).

... but I've been unable to find any recommendations on how much cream &amp; sugar to plan for ... obviously, it's going to vary depending on how many people are watching their weight and possibly regional, but do any of you have rough guidelines?  (or better advice for the coffee estimates in general?)
My company runs several coffee events per month. Here are some of my formulations that are a result of doing coffee tastings and events around Seattle: 

3-oz of coffee by weight, brewed with 62oz water will yield and aiprot or a standard 12-cup pot of coffee (60-oz brewed coffee or 7 servings if you are using 8-oz hot cups). For coffee gigs I bring 1-pound of regular and 3-oz of decaf coffee per 25 guests. So for 50 guests you will need 2-pounds of regular and decaf is never more than 20% (even after dinner). So for 50 guests you will only need a half pound of decaf. And will probably not use more that one pot of decaf coffee.

Cream: 1-pint half &amp; half per 25 guests. We just put the carton of half &amp; half in a small bowl of ice. We use Organic Valley half &amp; half with the little plastic cap/spout. It works well and is one less thing to clean up after the gig. 

Sugar: 5 packets per 25 guests.  

If you are worried about getting hit hard with coffee drinkers just double all of the above.