Configuring a 40 year depreciation key for MACRS

Hello All,

How do I configure a 40 year depreciation key for MACRS where the percentage is fixed from year 2-39, but year 1/40's depreciation depends on the month it was placed in service.

E.g. if the asset was placed in service in January, it should depreciate 2.461% in the first year and it should depreciate .017 in the last year, but this percentage will change in both year 1 and 40 if the asset was placed in February, March etc.

Please advice.