Sikh youth did successfully file for political asylums up to 1994, with 80-90% of them being false claims. With years of political instability & rampant corruption, Punjab have been left behind in growth compare to most parts of India. Instead of States, most Punjabis are now migrating to Canada, Australia & New Zealand.

the surveys of asian americans usually show low TFR (below replacement) except for a few small groups, like cambodian and laotian refugees (probably bangladehsi and pakistanis too). the fertility of hindu americans seems about replacement from pew religious ident survey. though if the population is peaking in fertility you are correct that the TFR can mislead. but anecdotally i think most people believe that this is due to massive immigration (you randomly meet lots of people who arrived in the 2000s in many large cities).

Also, I’m not sure why people are so sure the population growth is not due to births, especially considering the now child-rearing age of many Indian-Americans from the last census?

Not surprising considering how poor Punjab’s economic prospects are:

http://online.wsj.com/article/SB10001424052748703730804576322330472250792.html

http://online.wsj.com/article/SB10001424052748703730804576322352143277090.html

“Nice to know these new data but also the important data of Indian Americans to note is their achivements :”

Applause! Glad to know that a population largely drawn from India’s elite ranks is doing well. So what?

A joint Duke University – UC Berkeley study revealed that Indian immigrants have founded more engineering and technology companies from 1995 to 2005 than immigrants from the U.K., China, Taiwan and Japan combined.[18] A University of California, Berkeley, study reported that one-third of the engineers in Silicon Valley are of Indian descent, while 7% of valley hi-tech firms are led by Indian CEOs.

Indians along with other Asians, have one of the highest educational qualifications of all ethnic groups in the US. Almost 67% of all Indians have a bachelor’s or high degree (compared to 28% nationally and 44% average for all Asian American groups). Almost 40% of all Indians in the United States have a master’s, doctorate or other professional degree, which is five times the national average.

According to the 2000 U.S. Census, Indian American men had “the highest year-round, full-time median earnings ($51,094)”, while Indian American women had a median income of $35,173.[23]

Indian Americans own 50% of all economy lodges and 35% of all hotels in the United States, which have a combined market value of almost $40 billion.[25] In 2002, there were over 223,000 Asian Indian-owned firms in the U.S., employing more than 610,000 workers, and generating more than $88 billion in revenue.[26]

i think this is a good bet for the reason you give. the TFR for indian americans like most asian american groups is ~2.