and down to C20;
R20 = Believed unique
R19 = 2 to 5
R18 = 6 to 15
R17 = 16 to 50
R16 = 51 to 100
R15 = 101 to 250
R14 = 251 to 500
R13 = 501 to 1,000
R12 = 1,001 to 2,000
R11 = 2,001 to 3,500
R10 = 3,501 to 7,000
R9 = 7,001 to 12,000
R8 = 12,001 to 20,000
R7 = 20,001 to 30,000
R6 = 30,001 to 50,000
R5 = 50,001 to 100,000
R4 = 100,001 to 200,000
R3 = 200,001 to 350,000
R2 = 350,001 to 650,000
R = 650,000 to 1 million
N = 1 to 2 million
C = 2 to 3 million
C2 = 3 to 5 million
C3 = 5 to 6 million
C4 = 6 to 7.5 million
C5 = 7.5 to 10 million
C6 = 10 to 12.5 million
C7 = 12.5 to 15 million
C8 = 15 to 17.5 million
C9 = 17.5 to 20 million
C10 = 20 to 25 million
C11 = 25 to 30 million
C12 = 30 to 35 million
C13 = 35 to 40 million
C14 = 40 to 45 million
C15 = 45 to 50 million
C16 = 50 to 60 million
C17 = 60 to 75 million
C18 = 75 to 100 million
C19 = 100 to 150 million
C20 = Over 150 million