NEW YORK (CNNMoney.com) -- When it comes to pay, big business commands the bulk of attention, from the eye-popping pay packages of Fortune 500 CEOs to salary comparisons of the rank-and-file at the world's largest corporations.

But half of all private-sector employees make their living working at small businesses.

Salary.com on Wednesday released a survey of 1,800 companies with 500 or fewer employees across 50 industries to spotlight the earnings of small-business CEOs and of their executives heading up the company's major functions.

CEOs (or small business partners or owners) make a median base salary of $233,600, the survey found. Combined with bonuses and commissions, their median total cash compensation rises to $290,300.

Drilling down by industry, the highest median salaries are paid to CEOs in manufacturing ($254,700) while the lowest are paid to small-business chiefs in retail trade ($169,500).

In terms of median total cash compensation, however, CEOs in mining ($408,300), real estate ($350,000) and finance and insurance ($303,600) rake in the most, while CEOs in educational services ($227,100), information services ($222,000), and other services ($197,500) take in the least.

Among the executives who headed up key functions for a company, those who head up the legal department are the highest paid both in terms of base salary ($194,500) and total cash compensation ($244,800). On the bottom rung are office managers, whose median salary ($45,000) and total cash compensation ($49,000) come in at nearly half that of most other department heads.

Just as with large companies, the pay scale in small companies tends to increase along with company size and revenue and often is higher at publicly held firms.

Geography pay trends also follow those at their big-time cousins. Executives at small businesses typically are paid more in the Northeast and West than they are in states in the Midwest, South and Mountain regions.

There was one big exception. In Salary.com's tally of the top 5 areas for average CEO pay (the mean this time, not the median), Tennessee came in at No. 3 with a median base salary of $300,500, just below New York ($321,800) and the District of Columbia ($395,400).

------------------------------------------

New ways to get rich on the Web

Launch a business after 50

Fastest growing small companies: See why Goodrich Petroleum (Charts), Green Mountain Coffee Roasters (Charts), LoJack (Charts) and Websense (Charts) make the list