iPhone 5S sales outpace 5C two to one -- analyst

Apple's iPhone 5S is more than twice as popular as the company's iPhone 5C, according to a new report.

During September, the iPhone 5S accounted for 64 percent of all Apple smartphone sales, easily topping the iPhone 5C's 27 percent share, according to data obtained by All Things Digital from research firm Consumer Intelligence Research Partners (CIRP). Just 9 percent of customers bought the iPhone 4S last month.

Despite its lead in September, the iPhone 5S might not always be such a popular choice among consumers, CIRP co-founder Josh Lowitz told All Things Digital in an interview published on Monday. Historically, the latest and greatest iPhone handsets perform well among early adopters, but as time goes on, more consumers enter the market and take the opportunity to save some cash on lower-end products.

That is essentially the scenario that played out last year, according to CIRP. During October 2012, the iPhone 5 scored 68 percent of all Apple smartphone sales, easily outpacing the 23 percent share for the iPhone 4S and the iPhone 4's 9 percent sales share. Soon after, however, Apple's legacy products started to close that gap.