Professionals across the technology industry have enjoyed significant increases in salary over the past year, especially those who work in cloud, data analytics, and other in-demand segments. According to the new Dice Salary Survey, the average technology salary leapt 7.7 percent year-over-year, to $96,370 annually. (Nor were those increases limited to full-time workers; contractors also saw their annual pay increase.)

But why did those salaries increase? Those tech pros surveyed gave a number of reasons:

As you can see from the above image, a full 38 percent of respondents said their increased salary was due to a merit raise. ‘Changing employers’ came in second at 23 percent. Other potential reasons—such as overtime, counteroffers, or a mandated company-wide increase—racked up far lesser percentages, with certifications totaling a mere 0.6 percent.

What are the lessons in this? First, jumping jobs can get you paid more. Most tech pros know that, which is why the rate of voluntary quits tends to stay high when the economy’s doing well and employers are clearly willing to pay top dollar for skilled workers. Dice’s analysis of government data found the level of voluntary quits among tech pros at 519,000 and 500,000 in October and November, respectively, the latest months for which data is available; those numbers dovetailed neatly with low unemployment, suggesting a widespread demand for technology skills.

Second, making a noticeable difference at work has a very real effect on salary. That makes it especially important to not only highlight your accomplishments on your résumé (which really only helps when you’re looking for a new position), but effectively promote your work to your boss and colleagues; your future pay could depend on it.