As a former federal employee as an engineer my income increased from 50K as a new hire in 1996 to 72K in 2000, when I left to work for a company. 44% salary increase over 5 years.
Fed gov’t workers at my former employer increase at COLA (cost-of-living adjustment) e.g. 3% per year, plus locality adjustment of ~1% per year (SD has risen higher than other areas), plus merit pay increases of 1-2% per year. This averaged out to about 5-6 % per year for most people. Over 5 years this puts those in the 25% range.