The figure, recorded in the first Direct Marketing Material Prevention Report on industry performance, far surpasses the 2009 target of 55% and the 70% goal for 2013.
Postal consultancy company Onepost, which provides independent postal advice and management, said it was delighted that the industry had taken on board the environmental challenge.
Marketing manager Luan Wise said: "By exceeding these targets, our self-regulatory activity is clearly starting to pay off."
Onepost has attributed some of the UK's success to Royal Mail's Responsible Mail initiative, which offers lower prices for environmentally-friendly direct mail.
She said: "A client may not be able to meet all the criteria to achieve the postal discount, but if they can use any of the guidelines as a starting point for environmental best practice, then that's a positive move."
The Responsible Mail criteria are aligned with the requirements of PAS 2020, and involve responsible sourcing and recyclability of pack contents. Wise said that, most notably, the mail packs include a clear recycling message.
"From research we have conducted, we know that consumers believe this to be a mandatory requirement and are surprised that it isn't."
She added that the recycling target had also been met because it is now much easier to recycle, with regular kerbside collections making it easier for consumers.
"Environmental issues remain high on the agenda in 2010 and 2011, and it's important for consumers to recognise the efforts our industry is making so we can overcome the 'junk mail' tag," she said.