The average worker at the investment banking unit of JPMorgan Chase (JPM) made $369,651 last year, according to numbers (see page 10) released Friday in the bank’s fourth-quarter earnings report. That’s down 2% from a year ago and in line with the investment bank’s 4% annual profit decline.

The bank actually set aside a bit more in 2010 to cover employee pay and perks. Compensation expense hit 37% of the investment bank’s annual revenue, up from 33% in 2009.

Chief financial officer Doug Braunstein said on a conference call with analysts Friday that the bank doled out more pay because it spent 2010 on a bit of a hiring spree. Employment at the investment bank rose to 26,314 workers from 24,654 at the end of 2009.

Braunstein said the bank’s payout ratio was in line with its guidance for the year, and that JPMorgan plans to pay at roughly the same clip in 2011.

Among the remaining publicly traded banks, JPMorgan’s investment bank comes the closest to offering a comparison to Goldman Sachs (GS), which is due to report its 2010 earnings and aggregate compensation numbers next Wednesday.

The average Goldman banker made a shade under $500,000 last year, and like JPMorgan, Goldman has had a highly profitable year. But it too has been on a hiring spree and is under increasing scrutiny in Washington, which could give managers an incentive to push pay numbers down a bit. Relatively speaking, of course.