New Delhi, Oct. 25 -- A rather touchy issue that often comes up for discussion is the distribution of income in the country. The problem is that there is limited data to ascertain how income is distributed.

Agriculture, for example, is a black hole as no one knows how much income is generated by those associated with the sector. That also holds for certain services, especially real estate and mom-and-pop shops where financial dealings are opaque.

But one definitive data-set is on income earned, provided by the income tax department. The total number of income tax returns filed and incomes declared are useful measures to get some sense of how income is distributed. This gives a fair idea of the overall purchasing power of a major segment...