Calculating Access Demographic for Primary Index - forum topic by quest

Hello Friends,
1) Access Demographics:
Is there a formula to calculated access demographic for a primary index in Teradata?
For secondary index, the following formula is often used.
Access Ratio = (Typical rows per value) / (Rows in Table). Lesser the value, better the candidate for NUSI. But alternatively, isn't it if the value is 1, then its ideal candidate for PI?
2) Volatility Demographics:
Is the volatility scale defined as 0-9 or 0-10?
Appreciate.