German shoppers return roughly 12 percent of online purchases, a new poll by digital industry association Bitkom shows. Two years ago, the figure was 10 percent.

One-third of shoppers said they send back every tenth item, 14 percent admitted to returning a quarter of all purchases.

"The share of returns is extremely high and rising steadily, especially in certain sectors, like the fashion industry," says Julia Miosga, who heads Bitkom's trade and logistics department.

The 14 to 29-year-olds are the worst offenders, with a hefty 18 percent of purchases being returned.

Overall, women return 15 percent of items bought online, men only make up 9 percent of the total figure.

Retailers are increasingly looking for ways to make it easier to buy the right product and size online by giving more detailed information – specifically about clothes – via chats, product descriptions, 360 degree pictures and videos. Some also reward honest feedback with vouchers and discounts.

'Snap and send back'

In the UK, Europe's largest online shopping market, another trend is emerging. According to a recent poll by credit and debit card firm Barclaycard, one in 10 British shoppers admits to buying clothes online purely to take pictures of themselves for a "hashtag moment" on Instagram and other social networks.

The trend has been dubbed "snap and send back," with men more likely than women to return items after wearing them once. In the Barclaycard poll, it was the 35 to 44 year-olds who were the worst offenders.

"We know from our research that returns are having a big impact on retailers, with a huge figure of seven billion pounds [€7.8 billion, $8.8 billion] a year in sales that they potentially can't recognize," George Allardice, head of strategy at Barclaycard Payment Solutions said.

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Bitkom says retailers often find it difficult to resell items that have been sent back as they are damaged or no longer in pristine condition.

In Germany, online shopping made up 10.5 percent of total sales in 2017, according to trade association HDE. Fashion and consumer electronics account for around 50 percent of online turnover.

In the UK, Europe's largest e-commerce market, online sales made up 16.3 percent of total retail sales in 2017, according to Britain's Office for National Statistics (ONS).