Starting from around 36 years ago, as a child, as far as I remember: Cancer, car accident, old age, cancer, cancer, organ failures (age related) ..
But around 70% of our family's kennel breeding puppies came out well alive for a long time, this means: longer than the contact with their new owners was existing, as such > 6-8 years regularly. None died in the first three years, which is quite a good ratio (as it is not uncommon for some of those two breeds to get cancer quite early).
Ended before the millennium change, as our (aunt side) kennel closed down. Means there were just our own dogs and then dog anymore. This was before and at the start of my own owned dogs.
Often cancer, often old age. Sometimes internal failures, like diabetes, kidney enlargement, bone tissue changes, mostly related to old age. One died due to poison baits thrown above our fenced area. One of the reasons I am controlling like a blood hound what all cared-for dogs pick into their snouts.
Unfortunately cancer and old age correlate. Like with humans.. the risk raises above 60, even more noticeable above 70. And that's "just" 5 to 9 years, depending on breed and size - in age comparison for dogs.