These Doggie Figures?
Number of dogs worldwide. Around 525 million. At 75.8 million, the U.S. has the highest dog population in the world. France has the second highest with 8.8 million.
Reproduction rate. One female dog and her offspring could produce 67,000 puppies in 6 years.
Number of words dogs can remember. Somewhere between 150 and 200. A few dogs have super-canine abilities in this area, though. One collie is known to have learned over 1,000 words.
Size differential. Dogs can vary in size from a 150 lb. Great Dane to a 2 lb. Chihuahua.
Sources: MSPCA Angell, Dr. Stanley Coren, The World Health Organization.