Influence of experience on wage

What do you mean by "more experience"? This could mean either more experience in a particular position at a particular company, or more experience in a particular job field, or simply more years working (because older).

Someone who has had the same exact job title for a very long time (as opposed to moving from apprentice to journeyman to master over a career) may have low skills and/or be stuck in a low-skill (thus low paying) job.

Older (i.e. middle aged or elderly) workers might have a lot of job experience but only be working part-time to supplement Social Security; and PT work often pays a smaller weekly wage; or they might be reluctant to agitate for a raise based on experience for fear of being replaced by younger, entry level workers at less cost. This is particularly true in a job market where unemployment is high (as in 1980) since replacement workers may accept lower pay for employment. (When they do, the correlation changes; but in 1980 that had not yet happened.).

Another possibility is that in 1980 because of life expectancy differences between males and females, and/or youth prejudice which favored younger males for jobs but permitted older females, and because females tended to earn much less than males (e.g. secretarial work), more experienced (i.e. older) workers were skewed toward lower paid women workers.

What are your results for other years before and after?