Staff numbers were also down by 5% and the number of visits declined by 3% - making a 14% decline over the last five years – the research found.
CIPFA chief executive Rob Whiteman said: “Cuts in local authority funding are forcing councils to make difficult choices about which services they can afford.
“Unfortunately for libraries and library users, this is a low hanging fruit that continues to be picked.”
Whiteman added that it wasn’t all “doom and gloom”.
Volunteer numbers were up by 8% (and 43% since 2012), demonstrating that libraries remain import community assets.
“But, to really ensure that libraries are able to thrive, local authorities need adequate and sustainable levels of funding.”
Despite declining visitor numbers, the country’s most popular libraries continue to attract more than 1 million visits a year.
In 2016-17, the five most popular libraries were:
Library of Birmingham 1,601,520 visits
Central Manchester 1,474,655
Wembley Library 1,389,199
Woolwich Centre Library 1,187,332
Croydon Central Library 941,282
In terms of issues per annum, the busiest five libraries were:
Carlisle
Norfolk and Norwich Millennium
Worcester – The Hive
Llanelli
Cambridge Central
Almost 193 million books were issued in 2016-17, down 6.3% on the previous year, and down 25.1% over the last five years. Around 16.4 million audio, visual, electronic and other materials were issued, down 2% on last year and 15.4% over the last five year.
Adult fiction remains the popular book type issued by libraries, followed by children’s fiction.
Total net expenditure on British library services was £853,108,000 in 2016-17, a 7.2% decrease on the previous year.
Income was £81,435,000, up 5.9% on 2015-16.