I also stumbled across an article on calculating a dog's age...thought it was worth sharing this:
According to this, Comet the Dog and R are about the same age!
"The official formula, according to the American Veterinary Medical Association, equates the first year of a medium-sized dog's life to 15 years of a human's. The dog'...s second year equals nine years for a human. And after that, every year feels like five for a dog.
=> Click here to calculate your dog's age