A percentile score closer to 50 for Nifty50/NSE500 will reflect broadly a market where random portfolio distribution has equal chances of returns above and below returns of Nifty50/NSE500. (And so, near equal measures of luck and skill). Similarly, a very low percentile of Nifty50TR/NSE500TR would mean almost all random portfolios have given much higher returns, giving a sense of luck or rising tide lifting all boats.