Indians have emerged as the third-largest immigrant group in the US behind Mexicans and the Chinese with their number touching nearly 1.9 million in 2011, according to a US think tank.

The share of Indian immigrants among all foreign born in the US has grown to almost 5 percent of the country's 40.4 million immigrants in 2011, noted an article published in the Migration Policy Institute's online journal, the Migration Information Source.

Indian population has grown to over 150 times its size since 1960, when the slightly more than 12,000 Indian immigrants represented less than 0.5 percent of the total immigrant population of 9.7 million immigrants.

Indians' share of Asian immigrants in the United States has been increasing steadily since 1960, making it the third-largest sending country overall and the second-largest Asian sending country after China.

As a group, immigrants from India are better educated, more likely to have strong English language skills and arrive on employment-based visas, and are less likely to live below the federal poverty line than the overall foreign-born population, it says.

They are also more concentrated in the working ages than immigrants overall, and Indian-born men outnumber Indian-born women.