What was the question for this implicit rationale, and corresponding answer?
To answer the above question, the relevant sentence is: Islam is the second largest religion in India, with 14.2 % of the country's population or roughly 172 million people identifying as adherents of Islam (2011 census) as an ethnoreligious group.
 The answer: 14.2 %
The question: Islam is the second largest religion in India, with 14.2 % of the country's population or roughly 172 million people identifying as adherents of Islam (2011 census) as an ethnoreligious group. Islam first came to the western coast of India when Arab traders as early as the 7th century CE came to coastal Malabar and Konkan-Gujarat. Cheraman Juma Mosque in Kerala is thought to be the first mosque in India, built in 629 CE by Malik Deenar. Following an expedition by the governor of Bahrain to Bharuch in the 7th century CE, immigrant Arab and Persian trading communities from South Arabia and the Persian Gulf began settling in coastal Gujarat. Ismaili Shia Islam was introduced to Gujarat in the second half of the 11th century, when Fatimid Imam Al-Mustansir Billah sent missionaries to Gujarat in 467 AH / 1073 CE. Islam arrived in North India in the 12th century via the Turkic invasions and has since become a part of India's religious and cultural heritage. Over the centuries, there has been significant integration of Hindu and Muslim cultures across India and Muslims have played a notable role in economics, politics and culture of India.

Answer this question: how much of india's population is muslim?