Visual Cues - Expression for % rank

[#1]

Hi,

Does anyone know what expressions i need to add so that i can add visual cues for 3 different columns based on % rank?

E.g i want columns session count, total duration (hrs), avg duration (hrs) to be visually represented by the following:

• Green - top 25% of value
• Amber - 25-75% of value
• Red 75% of value

Any Ideas?