It's been a while since I bought one so it's possible some manufacturers have done away with the practice. It's probably a cost saving measure and/or so they can sell you a chart. I'll have to look at the taps next time I go to the hardware store.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.