China, the world’s largest smartphone market, saw handset shipments suffer their biggest decline ever during the last quarter, according to a new report from market research firm Canalys.

Compared to the same period last year, shipments were down 21 percent during the first three months of the year, with Chinese consumers buying 91 million devices. Q1 2018 was the first time since the fourth quarter of 2013 that shipments failed to reach or pass 100 million units.

While a decline had been expected, analysts were surprised by its size. “Eight of the top 10 smartphone vendors were hit by annual declines, with Gionee, Meizu and Samsung shrinking to less than half of their respective Q1 2017 numbers,” the report read.

The reason behind the slump could be something we're familiar with in the West: a lack of variation among new phones and too many ad campaigns. “The level of competition has forced every vendor to imitate the others’ product portfolios and go-to-market strategies,” said Canalys research analyst Mo Jia

Despite posting yet another record quarter, Samsung has issued warnings about a stagnating smartphone market. It sold just 2 million devices in China during Q1. Apple also struggled, falling down to fifth place in terms of total number of shipments. The top four companies— Huawei, Oppo, Vivo, and Xiaomi—made up 73 percent of all shipments in the country for the quarter.

Xiaomi, which overtook Apple into fourth place, was one of the brighter spots. Its shipments were up 37 percent YoY to 12 million units, though supply problems did mean it had a poor Q1 2017. Huawei, the top phone company in China, also grew, albeit by only 2 percent.

Canalys predicts that the second quarter of the year will see growth, thanks to new flagships from Oppo, Vivo, and Huawei, but believes there will be an overall decline during 2018.