| Classification | Prevalence rate (per 100,000) | Countries |
| Very high | 170–350 | Canada, Sweden (Varmland), Finland (Seinäjoki and Vaasa), Scotland, and most of Ireland |
| High | 70–170 | Most of United States, Norway, Sweden (Västerbotten), Denmark, Finland (Uusimaa), Iceland, England, Ireland (Wexford), Germany, Austria, Switzerland, Belgium, Italy, Turkey, Slovenia, Croatia, Czech Republic, Luxembourg, and Netherlands |
| Medium | 38–70 | Southern United States, Russia, most Australia, New Zealand (south), Faroe Islands, Poland, Estonia, Spain, Greece, Hungary, Serbia and Montenegro, Bulgaria, Belarus, Israel, Latvia, Lithuania, Moldova, Portugal, and Ukraine |
| Low | 13–38 | Australia (Queensland), New Zealand (north), Kazakhstan, Romania, India, Jordan, Saudi Arabia, Martinique, Argentina, South Africa, Brazil, Bahrain, Barbados, Lebanon, Malta, Morocco, Slovakia, Tunisia, United Arab Emirates, and Uruguay |
| Very low | 0–13 | Japan, Mexico, China, Taiwan, Malaysia, Thailand, Kuwait, Panama, Colombia, Afghanistan, Algeria, Bahrain, Cameroon, Chile, Costa Rica, Cuba, Ecuador, Guatemala, Guinea, Honduras, Iraq, Malawi, Mongolia, Nicaragua, Nigeria, Paraguay, Peru, Qatar, Republic of Korea, Singapore, Benin, and Senegal |
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