Keeping Background Colour the same until Certain Criteria is Met

[JPC1972]

Hi
I am Using CR 10 and trying to change the background colour when a certain condition is met (number value).No problem here but i want to keep the same background colour until the number value is increased. The value may change in between.The normal background colour of the report is nocolor.

Value
20 (color is nocolor)
301 (color changes to blue and stays until value=302)
30 (color still blue)
60 (color still blue)
302 (color blue but next record is nocolor)
30 (color is nocolor)

I hope this makes sense