Universal Rarity scale

URS-0 None known

URS-1 1 known, unique

URS-2 2 known

URS-3 3 or 4 known

URS-4 5 to 8 known

URS-5 9 to 16 known

URS-6 17 to 32 known

URS-7 33 to 64 known

URS-8 65 to 125 known

URS-9 126 to 250 known

URS-10 251 to 500 known

URS-11 501 to 1,000 known

URS-12 1,001 to 2,000 known

URS-13 2,001 to 4,000 known

URS-14 4,001 to 8,000 known

URS-15 8,001 to 16,000 known

URS-16 16,001 to 32,000 known

URS-17 32,001 to 65,000 known

URS-18 65,001 to 125,000 known

URS-19 125,001 to 250,000 known

URS-20 250,001 to 500,000 known

etc.