I don't have an exact number, but it seemed like we were out in the field 6 to 8 months out of the year. I remember it was mostly cold and wet. And I remember eating C rations (frozen a lot of the time because the heaters in the "tracks" (armored, tracked vehicles) never worked. I found an interesting link to the rations we lived on (I liked nearly all of them, even the ham and eggs).