Sensex, in 1978 was 100 and today it is 32400. CAGR for 39 years is 15.98% and add to it a dividend yield of 1.5%. Total CAGR = 17.5%. Do you mean best investors (very small percentage of investing fraternity) beat index only by 2.5% ?
I assume that these best investors are retail investors and not fund managers or HNIs.