You are talking about 14th FC. Now 15th FC is already creating ruckus in southern states as it has suggestions to allot funds based on 2011 population as opposed to 1971 population in previous FC. Even 14th FC has 10% weightage for 2011 population.
Between 1971 and 2011, Kerala and Tamil Nadu had population growth of 56% and 75% respectively – the lowest among all states.
On the other hand, Uttar Pradesh, Bihar, Madhya Pradesh and Rajasthan saw an explosion in their population. Their combined population growth was nearly 50 million higher than the national pace of growth can justify.
Why Southern States are Rallying Together Over the Terms of the 15th Finance Commission - The Wire