I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "According to Johnson and Grim (2013), Buddhism has grown from a total of 138 million adherents in 1910, of which 137 million were in Asia, to 495 million in 2010, of which 487 million are in Asia. According to them, there was a fast annual growth of Buddhism in Pakistan, Saudi Arabia, Lebanon and several Western European countries (1910–2010). More recently (2000–2010), the countries with highest growth rates are Qatar, the United Arab Emirates, Iran and some African countries."?
Answer:
Which period was being studied about Iran's Buddhism adherents?