Before revision:  We then characterise the asymptotic behaviour of this important quantity  and study the effect of the correlation  .
After revision:  We then characterise the asymptotic behaviour of this important quantity and study the effect of the correlation . Our results show that decreasing the correlation among payoffs (namely, of a strategist for different group compositions) leads to larger mean numbers of (stable) equilibrium points, suggesting that the system or population behavioural diversity can be promoted by increasing independence of the payoff entries .