One of the things we learn by looking at wages over time is that there is a great deal of variance. What this means, is that there is not one experience, one outcome, that is the same for everyone that completes a college degree. Over time, wages increase. For some individuals they increase more, for others they increase less. We also learn that salary compression is a real thing - new hires are often hired at wages that exceed wages of employees that have been in place for some years. Because of this, later years of graduates may show markedly higher wages.
Notice how the upper ranges grow wider in the later years following degree completion. This indicates much greater variation in outcomes. This occurs for a number of reasons including earning advanced degrees, certifications, licenses, and sometimes just being lucky to be in the right place at the right time. Success is often attributable to personal skills - the ability to get along with others, communicate well, problem-solve, and identifiying opportunities when they show up.