A small improvement in the public-sector absence rate helped the fall, but the public rate remained "significantly" higher than the private-sector rate, according to a report by the CBI.
Employees took 180 million sick days last year, averaging 6.4 days each, down from 6.7 days in 2007 and the lowest since the CBI survey began in 1987.
The impact of staff absence was said to remain "considerable", with the absences costing employers about 16.8 billion last year, plus indirect costs from reductions in customer service and delays to teamwork.
Workers pulling "sickies" was still a problem facing UK companies, according to research.
Surveyed by the CBI, senior human resources staff at 241 public- and private-sector organisations estimated that 15 per cent, or 27 million sick days, were not genuine, costing the country 2.5bn a year.
Katja Hall, the CBI's director of employment policy, said: "The rate of absence has come down, but it still costs the economy billions. If absence levels across the board could be reduced by 10 per cent, the economy would see annual savings of just under 1.7bn."
Public-sector workers took an average of 8.3 days off last year, 43 per cent higher than the private sector figure of 5.8 days.
The public sector's record has improved since the last CBI absence survey in 2007, when the average was nine days.
Ms Hall said: "Although the rate of absence has fallen in the public sector, it is still a lot higher than in the private sector, and this should be addressed, especially given that the public finances are strained.
"We estimate that 5.5bn could be saved by 2015-16 if the public sector matched the private sector's absence rate."