Most of my family's dogs are/were relatively long-lived. The others that didn't live long usually ran away for whatever reason. We never found them again. What a shame, they were nice dogs too.
Let's see.. at the moment we have an Aussie shepherd, he's 12 right now. Most likely will live until 16-18. Two jackrussel terriers, one is 4 and the other is 9. They'll probably live until 15-20 too. Hopefully.
Dogs we had before... first one was a terrier (forgot what kind, it was the smaller version of the Airdale). She was 16. A year later, her sister died at 16 also.
Then my beloved black dog, I think a collier & labrador mixed. He died of an infection in August 1998 after I came back from a family trip. My brother and I cried as we buried him in a special place (at that time we usually were too tough to cry that much). Took a while to get over that dog, and we still miss him. He was 17.
We also have a new puppy. He gives the younger JRT and the Aussie shepherd a run for their money while playing frisbee.
So... I feel for your losses. We are staunch dog people and we love our dogs.