Independent workers — those who don't have a payroll job at all, or who perhaps divide their time between a full- or part-time payroll job and freelance work on the side — are growing in numbers. And three major trends point to some of the shifts in pay and attitudes among them.

That's according to a study from MBO Partners, which identifies the first trend as a strong job market that's making it easier for independents to compete, on their own terms, for work. A current unemployment rate of 4.3 percent coupled with 6 million job openings and an economy that last year added 2.2 million payroll jobs in the past year is giving many independents with in-demand skills a chance not only to find additional work, but to ask for — and get — more money for it.

Some, in fact, are making more money than a payroll job would offer; this year — for the sixth year in a row — the number of high-earning independents has risen. That's 3.2 million people — almost one in every five of full-time independents (those who work independently more than 15 hours per week). And those high-earners make more than $100,000 a year.