There is exactly one adult ABN person I know of in my metro, and he is also ABPP. On second thought, he may have let his ABN lapse.
Not sure about ABN's numbers, but ABPP-CN has been steadily increasing for years.
Edit: His ABN has not lapsed, but he is the only ABN member in my entire state. I was curious and checked a neighboring state, which also has only one active ABN member. These are not small states.