Apple’s iPhone sales in the U.S. are starting to flatline, according to data from the Consumer Intelligence Research Partners.

Growth of the iPhone install base in the U.S. has been on a downward trend for years now, but CIRP’s latest report reveals that growth was at its slowest rate ever during the first quarter of 2019.

In March 2019, Apple’s U.S. iPhone base hit 193 million units, based on CIRP’s estimates. If accurate, that would represent a meager 2% growth compared from the last quarter, and just 12% compared to March 2018.

Apple stopped sharing quarterly unit sales for its products with investors, so it’s harder to gauge now exactly how much iPhone sales are slowing down. Some analysts estimate that sales have dropped 20% to 30% year-over-year. Apple has been able to make up for the lower sales with higher priced iPhones, but CIRP co-founder Josh Lowitz says investors should wonder if Apple will be able to compensate with sales outside of the U.S.

“The US installed base of iPhones continues to plateau,” said Lowitz. “Relative to the most recent quarters, and especially to the past two or three years, slowing unit sales and longer ownership periods means that the growth in the number of US iPhones has flattened considerably.”

Services are receiving more emphasis from Apple now than ever before. Even though the company’s install base growth is slowing, the company hopes to tap into it with a bevy of paid-for-subscription offerings that can bring in more revenue from users. Apple News+ and Apple Music are already in full swing. Meanwhile, Apple Card, Apple TV+ and Apple Arcade should be making their way onto iPhones and iPads later this year.