Each year, the U.S. Department of State releases statistics on visa refusal rates by country. It lists every country in the world in alphabetical order with its visa refusal rate. In reviewing the refusal rate for visitor visas (B-1/B-2) last year, I reorganized the information so that the countries are listed by highest to lowest rates of refusal. You can find the list here.

You can find all the statistics here: https://travel.state.gov/content/travel/en/legal/visa-law0/visa-statistics/nonimmigrant-visa-statistics.html