Mobile payments are having a tough time gaining adoption in mature markets.

According to the annual “Connected Life” study by Kantar TNS, only a minority of internet users surveyed in countries like the US, the UK, Canada, France and Germany preferred the use of mobile payments to other methods.

In fact, China and Mongolia were the only two countries in which a majority of respondents said they favored using mobile payment platforms. China was something of an outlier, where 64% of respondents expressed a preference for mobile payments. Mongolia was close behind (63%).

The study, which surveyed internet users in 56 countries, found that just 39% of total respondents preferred the use of mobile payments. That figure sat at 45% in markets Kantar TNS defined as “emerging,” significantly higher than the 23% average in developed countries. The preference rate was highest in the “emerging Asia” region, at 48%.

China’s preference for mobile payments eclipses the average in the wider “emerging Asia” region by a significant margin, thanks to its comparatively developed digital ecosystem. The country has a relatively low rate of credit card adoption, allowing digital services like WeChat Pay to spread rapidly, especially in the country’s urban areas.

A June 2017 survey of urban WeChat Pay users in China by Tencent Research Institute found that 73% of respondents used cash when that was the only form of payment accepted.

Meanwhile, services like WeChat Pay have established themselves as an easy way to complete transactions in China. eMarketer estimates that 77.5% of smartphone users in China will use proximity mobile payments in 2018, compared with just 25.3% of smartphone users in the US.

There are a few factors holding back mobile payments in Western markets. According to a June 2017 survey by Paysafe, lack of knowledge was the primary reason mobile users in Canada, the UK and the US don’t use a mobile wallet. Other reasons included various security concerns, and some simply didn’t like taking their phone out to pay.

A November 2017 report on US mobile consumers by Deloitte stated that key obstacles to adoption in the country included “concerns about security and a lack of understanding of [mobile payments’] potential benefits.”

Regardless of such adoption barriers, providers such as Apple Pay and Android Pay are continuing to expand their reach globally. Last month, Android Pay launched in Brazil, Czech Republic, Slovakia, and Ukraine, bringing the total number of countries in which it’s available to 17—eight of which were added this year.