Globenewswire:

Apple Pay usage in the US is growing, driven by both increased frequency of transactions and the expanding base of iPhone 6 owners, according to The Auriemma Consulting Group (ACG) Apple Pay Tracker, which interviewed 500 iPhone 6 and 6+ owners between May 29 and June 15, 2015. Forty-two percent of US Apple 6/6+ owners reported having used Apple Pay, virtually identical to the proportions reported in two previous waves of the study conducted in February and April 2015. “While the proportion of users has remained stable, the denominator has grown through new iPhone and Apple Watch sales and the upgrade cycle. We’ve also seen the average number of transactions increase both in-store and in-app,” says Marianne Berry, Managing Director of ACG’s Payment Insights practice.

So the proportion of iPhone 6 users using Apple Pay is staying constant, but as the number of iPhone 6 users increases, Apple Pay use increases proportionately.

Logical.