That’s according to the International Data Corporation’s report published Thursday on worldwide tablet shipments for the second quarter of 2018.

The research firm said that overall shipments plunged 13.5% year-over-year in the second quarter to 33 million, underscoring the tough tablet market that has been steadily declining for some years.

One possible reason for the drop in tablet shipments might have to do with people and businesses appearing to be buying personal computers instead of the tablets, according to IDC senior research analyst Jitesh Ubrani.

Ubrani noted in the IDC report that while businesses seemed interested in so-called detachable tablets that function with removable keyboards, “those operating on tighter budgets have had very few options available to them and hence some have opted for traditional PCs.”

The IDC analyst seemed hopeful that cheaper detachables, like the newly released Surface Go from Microsoft (MSFT), would entice people to switch from their laptops.

“However, with the launch of the Surface Go, Chrome OS-based detachables, and hopefully a more affordable iPad Pro in the future, the detachable category still has a bright future, provided the performance and software lines up with users’ expectations,” Ubrani said in a statement.

Apple (AAPL) was the leading tablet company in the second quarter of 2018 having shipped 11.5 million devices, which was relatively flat year-over-year. Apple now commands about 35% of the overall market, the data showed.

“The launch of a newer iPad towards the end of the first quarter, combined with improvements to the OS and the renewed push into Education, seems to be paying off for the company,” IDC said in a statement.

Samsung was the second biggest tablet company, and shipped 5 million devices in the second quarter, which was a 16% year-over-year drop. IDC attributed the tablet decline to an aging Samsung tablet portfolio.

Huawei’s tablet shipments grew 7.7% year-over-year to 3.4 million, with the bulk of those tablets being sent to the Asia/Pacific region, but not Japan.

Amazon (AMZN) had the biggest drop in tablet shipments, with the online retailer shipping 1.6 million devices in the second quarter, which marked a whopping 33.5% drop from the same quarter a year ago.

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IDC attributed Amazon’s big drop in tablet shipments to a “saturated market,” presumably due to Amazon’s cheap Fire tablets, which the company has heavily discounted over the years, particularly around events like Black Friday.

A previous IDC report said that one reason Amazon is content to sell cheap Fire tablets is because “the company remains highly focused on acquiring additional Prime subscribers regardless of the type of device used.”