This is an Annual Trend Volatility of Income After Tax over 10 years. Trend Volatility is derived by subtract the log linear Estimated index value (in index value units) from the Actual index value and divide by the Estimated index value to derive a % deviation. Repeat this for each observation and average the .absolute. results to derive a % Mean Absolute Deviation. Express this result as a percentage. Required 11 latest fiscal year intervals. Income After Tax represents the sum of Income Tax (Total) and Income Before Tax for the same period.