15 Lacs PA to 20 Lacs PA = $24k - $32k per year
That's quite a lot than the range you would have to pay for a Software Engineer in Mexico, which goes between $18K and $27K (gross).
I guess that's why more and more USA companies choose to outsource to Mexico, to take advantage of the closer time-zones and somewhat more familiar culture.
I did not know that salaries in Mexico are in the range of 18K-27K USD pa; that sounds like a better deal for US based companies.
BTW, one should note that the major Indian outsourcing service providers (a.k.a the big three - TCS, Infy, Wipro) are already in Mexico.