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The CFB includes 16 probabilities of extreme sea level ranging from 100% to 0.001% AEP (or 1 to 10,000 year return periods).

Annual Exceedance Probability (AEP) describes the likelihood of being exceeded in any given year. For instance, an AEP of 1% has a chance of being exceeded 1 in 100 in any given year. In coastal design the reciprocal of an AEP is often termed as a ‘return period’. An AEP of 1% is equivalent to a return period of 100 years.