In Great Britain the Kennel Club maintains a list of “vulnerable native breeds.” This refers to breeds that were developed in the UK which register fewer than 300 individual dogs per year. There are currently about 29 breeds on this list, with more breeds on the Watch list, meaning they are close to Vulnerable status. Although the Kennel Club in Britain registers fewer dogs than we do in the U.S., the situation with purebred dogs in the U.S. is similar. While the Labrador Retriever - the top dog registered by the AKC for over 20 years - has tens of thousands of individual registrations every year, other breeds have far fewer numbers. Beyond a few popular breeds, most breeds have relatively small numbers of dogs registered each year. We have many breeds in the United States which register only a few hundred individual dogs per year.
Every breed can be trained to learn almost every command. However, some breeds learn a lot faster than others - making them a lot easier to train. These highly intelligent breeds pick up a command after only about five or six repetitions, they more often respond on the first time you give the command, and they remember commands even if they are not practiced often. They also learn commands even when the trainer is inexperienced and makes mistakes. So if you do not have a lot of the time to spend dog training, or you are the impatient type who gets frustrated easily, choose a breed which has a high ease of training rating.
In some cases, a breeds origin overlaps the boundaries of two or more countries; the dog is normally listed only in the country with which it is most commonly associated; for example, by its designated country according to the Fédération Cynologique Internationale (FCI). Some dogs, such as the Löwchen, have an uncertain origin and are listed under several countries.
Your dogs temperament should match yours. Do not choose a breed that is highly energetic if you are a couch potato. On the other hand, if you want a dog that will follow you everywhere around the house and who is always ready for a game of fetch or tug of war then you should consider a dog that is highly active and always has a lot of energy, instead of one of the lethargic breeds.