Urban and rural areas were classified in accordance with each UN member country's own definition for what they consider to be urban and rural.
By comparison, the urban-rural gap in developed countries was much smaller, with 87% and 81% of urban and rural homes having access to home internet in 2019, respectively.
Meanwhile, connectivity gaps in rural areas were the most particularly pronounced in the least developed countries, with 17% of these rural populations living in areas with no mobile coverage at all, and 19% of these rural populations being covering by only a 2G network.
"How much longer can we tolerate the significant gap in household connectivity between urban and rural areas?" ITU secretary-general Houlin Zhao said.
Looking at internet coverage, in most regions, more than 90% of the population have access to a 3G or higher quality mobile-broadband network, the ITU said in its report.
Africa and the former Soviet states that make up the Commonwealth of Independent States were the regions that faced the biggest gap in 2019, where 23% and 11% of their populations, respectively, had no access to a mobile broadband network at all.
Globally, almost 85% of the population will be covered by a 4G network by the end of this year, which would amount to a two-fold increase from five years ago, the report said. Annual growth has been slowing down gradually since 2017 however, with 2020 coverage only being 1.3 percentage points higher than 2019.
93% of the world population, meanwhile, will have access to at least 3G networks by the end of 2020, which is only half a percentage point higher than a year ago.
Along with the slowing down of internet coverage expansion, 2020 also saw the total number of mobile-cellular telephone subscriptions decline for the first time in history, according to the report.
During 2020, there were an estimated 105 mobile-cellular subscriptions per 100 inhabitants, which is down from 108 in 2019. The report stated that further research would be required to understand whether the dip was caused by the COVID-19 pandemic or other socio-economic forces.
In response to the slowdown of network coverage expansion and decline in mobile subscriptions during 2020, Zhao said infrastructure rollout needed to become an urgent issue for countries globally, especially as COVID-19 has forced many people to work and study from home.
"With the COVID-19 pandemic wreaking havoc on lives, societies, and economies around the world, many of our daily activities have moved online, throwing a sharp spotlight on global connectivity," ITU director Dorren Bogan-Martin added.
Despite the decline in global mobile-cellular subscriptions, international bandwidth usage continued to grow during the pandemic. According to the report, international bandwidth usage grew globally by 38%, exceeding the growth rate of the previous year by six percentage points.
Earlier this year, the ITU and World Health Organization (WHO), supported by the United Nations Children's Fund (UNICEF), worked with telcos around the world to text health information related to the pandemic to those without access to the internet.
"The goal is to reach everyone with vital health messages, whatever their connectivity level," the WHO and ITU said in a statement.