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ISO 8601 Guidance
accrualPeriodicity
Term
ISO-8601
Decennial
R/P10Y
Quadrennial
R/P4Y
Annual
R/P1Y
Bimonthly
R/P2M or R/P0.5M
Semiweekly
R/P3.5D
Daily
R/P1D
Biweekly
R/P2W or R/P0.5W
Semiannual
R/P6M
Biennial
R/P2Y
Triennial
R/P3Y
Three times a week
R/P0.33W
Three times a month
R/P0.33M
Continuously updated
R/PT1S
Monthly
R/P1M
Quarterly
R/P3M
Semimonthly
R/P0.5M
Three times a year
R/P4M
Weekly
R/P1W
Hourly
R/PT1H
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