Finnish operator DNA said the difference in mobile data use between age groups is large, even between millennials and generation Z. The Telenor unit said the average adult in Finland aged 18 to 29 used more than 91 GB of data with their postpaid subscription in August-October. This compares with an average of 49 GB for those in the 30-39-year-old bracket.

Pekka Vaisanen,  director of DNA's consumer business said that millennial are often referred to as a homogeneous group but the operator’s figures show that they are in fact very heterogeneous in terms of data usage.

According to DNA, 50-59-year-olds used about 31 GB in August-October, or about a third of what 18-29-year-olds do. The average data consumption by 40-49-year-olds in the sampling period was 44 GB.

Comparing use with the corresponding three-month period in 2019, the amount of data used by young adults has increased by more than 10 GB per age group on average. There will also be an increase in data consumption in older age groups during the year, but at a slower rate.

The largest single use for internet service by young adults is to watch video. Adults under 30 used an average of 39 GB over three months, or 43 percent of their total, for viewing. Those aged 40-49 used up to 46 percent of their data consumption for watching video, up from 37 percent last year.

Data use for social media by young adults was on average 14.8 GB, more than the average of all the other age groups combined. The biggest change in young adults' data use was for listening to music. The share of total data used to stream music jumped from 0.5 percent to 1.2 percent within a year.