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Coming up with an average is difficult because of the variables. It helps to know what airline(s) you're considering, and whether you're looking for saver awards (probable) or will settle for non-capacity-controlled (usually double mileage) awards.
To use UA as an example, it would be (for round-trip travel) 60K to the Caribbean, 120-125K to Asia, or 135K to Australia or saver or Star Alliance awards. Standard Awards (no capacity controls) are all twice that.