Let G be a finite group and let I ={g in G: g^2 = e} \ {e} be its subset of involutions. Show that G is abelian if card(I) => (3/4)card(G).

I don't really know how to proceed with this problem and to make use of 3/4. I've thought about group actions but my algebra is kind of rusty right now. Any help on how to proceed with the problem is highly appreciated. Thanks.