id	definition
A	Annually (Calendar Year)
C	Daily
D	Discrete
F	Flexible Interval (from Date X through Date Y)
M	Monthly Bucket (Calendar Months)
Q	Quarterly (Calendar Quarters)
S	Semi-Annually (Calendar Year)
T	Four week bucket (13 buckets per year)
W	Weekly Bucket (Monday through Sunday)
X	Weekly Bucket (7 day interval)
Z	Mutually Defined