The Amazon Fire Phone’s exclusivity with AT&T could be holding back early adoption for the high-profile smartphone, according to advertising group Chitika.

By analyzing millions of U.S. and Canada smartphone-based online ad impressions, Chitika found that North American usage of the Fire Phone only increased incrementally in the three weeks since its launch.

The study compares the usage growth of the Fire Phone to the LG G3, which saw its initial U.S. release on July 11, and the Droid Ultra, a Verizon-exclusive released on Aug. 20, 2013. Usage rose 0.06 percent for the G3 in the three weeks after its release, compared to a 0.02 percent rise for the Fire Phone. The Droid Ultra saw a similar 0.02 percent usage rise.

“Both the Fire Phone and Droid Ultra charted relatively similar growth rates following their respective launches, with the latter experiencing a slightly steeper rise,” Chitika said in a statement. “In this context, the somewhat mild adoption of the Fire Phone may be seen as an expected consequence given the smartphone’s carrier exclusivity.”

The study suggests lowering the price and widening availability as options for Amazon to generate more interest in the Fire Phone but concedes that Amazon may focus on improvements for the second generation of the phone.

Following a large-scale launch event, Amazon on July 25 released the Fire Phone in AT&T stores and online. Priced at $650 or $200 with a two-year contract, the Fire Phone comes with a one-year subscription to Amazon Prime.

The Fire Phone is highlighted by features like the Firefly button, which can recognize media and real-world objects, and Dynamic Perspective, which renders on-screen graphics in 3D by using front-mounted cameras.