Step 1: Understanding the Concept:
The question focuses on the demographic comparison between the two nations and its impact on per-capita indicators.
Step 2: Detailed Explanation:
While India has surpassed the U.K. in total economic size, the text notes a significant difference in population.
It states: "But, India has a population 20 times that of the U.K. and so its GDP per capita is lower."
This means that even though the total "pie" (GDP) is larger, it has to be shared among a much larger group of people, resulting in less income per individual compared to the U.K.
Step 3: Final Answer:
As per the passage, India's population is 20 times larger than that of the United Kingdom.