# stepUnits table used for both grib 1 and 2     
0 m  Minute
1 h  Hour
2 D  Day
3 M  Month
4 Y  Year
5 10Y  Decade (10 years)
6 30Y  Normal (30 years)
7 C  Century (100 years)
10 3h  3 hours
11 6h  6 hours
12 12h  12 hours
13 s  Second
14 15m  15 minutes
15 30m  30 minutes
255 255  Missing