This is the highest deposit figure since Help to Buy was introduced, with first-time buyers typically purchasing homes for £159,035.
Loan-to-values have fallen for all buyers, as they dropped by 2% from 77% in May to 75% in June.
There is a significant price gap between 75% LTV and 95% LTV mortgages, as someone with a 5% deposit would have to pay 69% more on their mortgage.
Simon Crone, Genworth vice president, mortgage insurance Europe, said: “Despite record low interest rates over the past few months, the lingering price gap between 75% and 95% LTV mortgages means those unable to stump up a 25% deposit – averaging almost £32,000 – face far higher monthly costs.
“For many, a deposit of more than 5% is simply not an option and failure to encourage lending at this level is resulting in a massive shortfall in first-time buyers.
“Rising house prices and a lack of supply are exacerbating the situation and leave hopeful first-time buyers scrambling to save a deposit as quickly as possible, before the dream of homeownership gets any further out of reach.”
He added: “The only way to overcome this and support the ambitions of homeownership is if affordable mortgages – those requiring just 5% or 10% deposits – are made available permanently through greater use of private mortgage insurance by transferring the Help to Buy 2 scheme to the private sector.
“Through use of private mortgage insurance, more building societies have already been able to support many first-time buyers by increasing the number that are able to access 95% LTV mortgages.
“Before Help to Buy comes to an end, this needs to extend to banks, who are typically more reliant on the government scheme, so that access to these loans does not tail off.”