Sanka is 97% caffeine free. How does regular coffee compare?

When I first heard this slogan I assumed they meant that Sanka had only 3% of the caffeine of regular coffee. But now I assume they meant it was 3% caffeine by weight.
After all, 2% milk has 2% fat. Regular milk has 3.5% fat, so 2% sounds very fat free but actually has over half the fat remaining.

So how does regular coffee compare?

You were right the first time:

It’s a simple enough calculation.

The bottle I have is 7 oz. and makes up to 105 cups. 7 oz. is 198 grams or 198,000 milligrams. Each cup therefore uses 1885 milligrams of coffee.

Instant coffee has 65 to 100 milligrams of caffeine per cup. So each cup is 3.44 to 5.30% caffeine.

So decaffeinated coffee can’t be 3% caffeine itself. It’s actually .10 to .16%.

And that’s using the old-fashioned 97% caffeine free numbers. Today’s decaf is 99.7% caffeine free, so a cup is .010 to .016% caffeine.

Not very much.

More info:

A normal serving of regular instant coffee powder is 2 grams, and contains 55 milligrams of caffeine.

A normal serving of decaffeinated instant coffee powder is 2 grams and has 2.1 milligrams of caffeine.

That is the equivalent of 96.18% less caffeine that regular instant coffee. If it was 3% of the weight, decaffeinated would have 60 milligrams per serving, or more than regular coffee. That does not compute.