Честотите се определят като много чести (≥1/ 10); чести( ≥1/ 100 до < 1/ 10); нечести (≥1/ 1 000 до < 1/ 100); редки (≥1/ 10 000 до < 1/ 1 000); много редки (< 1/ 10 000).
Frequencies are defined as very common (≥ 1/ 10), common (≥ 1/ 100 to < 1/ 10), uncommon (≥ 1/ 1000 to < 1/ 100), rare (≥ 1/ 10,000 to < 1/ 1000), very rare (< 1/ 10,000).