Pictured: Apple store in Shanghai by Flickr user Jon Skilling

When it comes to geographies, much has been written about Apple's (AAPL -0.57%) increasing reliance on growth from China. And that makes sense, as the country went from not even being listed as an individual operating segment in the company's 2012 annual report to being the company's second-largest segment by operating income. The combination of a large population and increasing GDP per capita have quickly turned the predominantly labor market for Apple into a nation of customers.

More recently, though, a slowing-growth outlook from the Middle Kingdom has scared investors as Beijing reported 2015's growth rate fell to 6.9%, below the country's official growth target of 7%. According to the International Monetary Fund, the country is expected to slow further in the upcoming years, with forecasts of 6.3% growth in 2016 and 6% in 2017. Whether this will affect Apple's sales path in the country is another question entirely, but it will be hard for Apple to maintain the 84% revenue growth rate in the country it had last year.

However, Apple's next potential growth opportunity bears potential remarkably similar to China's, as it's a heavily populated developing Asian nation with a comparatively high GDP growth rate. That country is slated to be the fastest-growing country next year, with the IMF estimating 7.5% GDP growth -- that country is India. 

An Apple store in India?
Recently, Apple filed an application to bring an Apple store to India, less than three months after the government relaxed rules relating to single-brand retailing. Before November, single-brand retailers with more than 51% foreign ownership needed to source 30% of their products in the country in order to open shop. In addition, these retailers were not allowed to use e-commerce, pushing Apple to partner with a network of franchisee-owned stores to sell its products.

One downside of this arrangement is that Apple has limited control of the outlay and oversight that makes Apple's retail stores the envy of the retailing world, with its stores responsible for the most sales per square foot. Apple stores function as both a shopping channel and as high-end marketing. Therefore, bringing a retail outlet to the country makes sense: According to a form the company filed with the government in early 2015, Apple reportedly increased its revenue in India over 44% from the prior year and now does more than $1 billion of revenue annually in the country.

In the fourth quarter, CEO Tim Cook mentioned he was "impressed" with progress in India and said the move to build an Apple store, if accepted by the Indian government, should increase exposure and grow future revenue in the country.

This is probably a longer-term project
While India is a great deal like China in many respects. There's one key aspect where the country falls far short of its slightly larger brethren: GDP per capita. The measurement, which is a close proxy for the average income per person on a yearly basis, shows the country comes up far short. For 2015, the International Monetary Fund estimated the average GDP per capita in China was $8,280. This is well below the United States' figure of nearly $56,000, but enough for upper-income consumers to buy Apple's high-end products.

For India, however, the GDP per capita figure is $1,688, making a $700 iPhone purchase a large part of a worker's annual income. Of course, this GDP per capita figure is an average, with wide variances in a country of nearly 1.3 billion people. Recently, there are faint signs of a growing middle class in India, with the country's smartphone market expected to become the world's second largest, pushing past the United States, in 2017. It's estimated that Apple has less than a 2% share of India's smartphone market.

If Apple's able to continue to grow its top line 44% in the country, India could be the next China for Apple investors looking for growth. That may sound far-fetched, but who would have thought five years ago that China would be Apple's second-largest market?