Returns current label mode.
Call this method to determine the current label mode. It can be one of the following enumerated values:
- LM_NORMAL - values are displayed as 0, 25, 50, 75, 100
- LM_2080 - values are displayed as 0 / 100, 25 / 75, 50 / 50, 75 / 25, 100 / 0
- LM_BASE_1 - values are displayed as 0, 0.25, 0.5, 0.75, 1.