by Brian Cornwell
[spreadsheet]
Description°
Frequency of Appearance*
Excessively Rare°
1 or fewer
Extremely Rare°
2 to 3
Very Rare°
4 to 6
Rare°
7 to 10
Scarce°
11 to 15
Not So Common°
16 to 25
Common°
26+
[/spreadsheet]
* in a typical 10 year period.
