5y
The comparison is against their last changed job because other companies are desperate to pay to secure them for urgent projects - most of our staff received at least 10% increment yearly and often a lot more, so much so that they are more than some of the very large IT companies. Most of our staff came in with not very good experience and they were trained with good mentorship till the level they were valuable to others that others are willing to pay more. We develop people's careers, giving them opportunities for them to learn and these are costs to the company.
My suggestion is for these people to come back 3 years later and do a comparison with their peers still in the company