Cappy, I cannot bring you the specific source of 40% off-hand, but that number is generally used by many scholars engaged in the Madhehi issue. One good place to look for might be Mahendra Lawoti's book "Towards a Democratic Nepal", which deals with issues of democratization of Nepal vis-a-vis the rights (or the lack thereof) of marginalized groups of Nepal. One of the key in resolving social problems is distinguishing between the DEMANDS and the CORE. Demands ("what") are usually peripheral to the problem; and if one can identify the CORE, i.e., "why", then it becomes easier to resolve the issue. For instance, all the demands being put forth by the Madheshi groups are there, from citizenship rights, to separate Madheshi state, to radically-charged separate state. In the process of attempting to resolve the problem, if we focus on those demands ("WHAT") only, I am afraid, there will be a lot of back-and-forth, laden with charges and counter charges, and we may never get anywhere. On the other hand, if one begins to focus on the "WHY", i.e., WHY the Madhesis are putting forth WHAT they want, we can see that the issue becomes that of equality and dignity. If then the state begins to recognize and address the WHY part, I believe the WHAT part begins to be pacified. Therefore, the Madheshi militancy is obviously not good, but bringing an end to it requires that we as a nation begin to treat the Madheshi Nepali with equal dignity, as real human beings.