This figure is down from the 10.3% recorded in 2019.
According to the lender, it helped 24,557 homeowners to purchase or remortgage last year.
This includes 5,424 first-time buyers, and 5,955 buy-to-let borrowers.
The total number of homeowners it helped to purchase or remortgage in 2019 was 29,727.
Looking to gross mortgage lending, this figure was seen at £4.5bn in 2020, down from 4.9bn.
The group’s net residential UK mortgage lending accounted for 3.9% of the growth in the UK residential mortgage market, down from 4% in 2019.
Over the course of 2020, the building society has outlined that it arranged over 25,000 mortgage payment deferrals.
The total number of members rose by 14,844 to over one million over 2020.
Overall, the lender recorded underlying profits before tax of £124.0m in 2020, down from £155.2m the year prior.
In addition, total profit before tax was £118.8m, down from £153.2m in 2019.
Profits have been impacted in the short-term by the increase in the group’s loan impairment charges of £25.7m, up from £0.5m year-on-year.
David Cutter, group chief executive of Skipton Building Society, said: “As a 168-year-old mutual, Skipton’s values are firmly rooted in helping people have a home and save for the future.
“We will always make decisions based on the long-term best interests of the business and our members, not shareholders.
“Over the years this consistent approach has seen us successfully navigate through the good times, and the difficult times. And COVID-19 brought this purpose to the fore.
“Whilst we still reported good group profits for the year, our financial results reflect a challenging period.
“Our mortgages and savings division has been heavily impacted by increased impairment charges and our estate agency division, Connells, saw all of its UK branches forced to close for two months.
“However, the resilience of Skipton’s business model has allowed the Society to maintain strong capital ratios throughout and we look to the future with confidence.
“In December, Connells reached an agreement with the Countrywide plc board and its major shareholders to acquire Countrywide.
“The combination of the two businesses is an excellent opportunity to extend Connells’ presence across the UK.
“The enlarged scale of the society’s estate agency operations should deliver enhanced returns for the society, and hence its members, over the medium and longer term.”
