NEW YORK—The global public relations industry grew by slightly more than 8 percent in 2010, ending the year with fee income of at least $8.8 billion and employing about 60,000 people, according to new research revealed this week by The Holmes Report.

The industry’s performance in 2010 represents a strong recovery after 2009, during which global PR revenues declined by about 7.5 percent.

The results form part of the Holmes Report’s 2011 Global Rankings report, which also ranks the 250 biggest PR firms in the world.

The independent public relations firms that provided fee income to The Holmes Report generated about $3.75 billion in revenues in 2010, an increase of about 10 percent over 2009 levels.

Growth was somewhat slower at the publicly traded holding companies that did not provide revenue numbers to our report (WPP Group, Interpublic, Omnicom, Publicis Groupe, Havas and Chime) but nevertheless provide their numbers publicly. Revenues at those firms were up by about 6 percent to around $3.85 billion.

In addition, the networks of independent public relations firms submitting numbers report combined revenues of around $900 million. While much of that revenue is included in the rankings as a result of member firms reporting separately, at least $350 million in revenue comes from member firms that elected not to submit to our rankings.

In other words, we have identified and confirmed approximately $7.95 billion in worldwide public relations fee income.

A number of firms absent from the rankings—M: Communications, Joele Frank Wilkinson Brimmer Katcher, Sard Verbinnen, Glover Park—and firms listed in various other league tables but not in The Holmes Report 250) between them generate at least another $400 million in fees. And there are literally hundreds smaller firms, most of them generating less than $1 million in fees (but some of them generating considerably more), listed in directories in the US and UK or in the membership ranks of public relations trade groups around the world.

Add in that income, and it is clear that the PR agency business generates at least $8.8 billion in worldwide revenues—and probably considerably more.

Given that the firms that provided both revenue and headcount information generated revenue per capita of $148,795, it seems likely that the agency business as a whole employs more than 59,000 people.