What is the average percentage change from starting to mid-career salary across all majors in the dataset?

What is the average percentage change from starting to mid-career salary across all majors in the dataset?: a task in SmolDataEnvs-harbor-train-sandbox: 📊 SmolDataEnvs: Harbor (train) (Harbor dataset). Files (in /home/user/input, no subfolders): - degrees-that-pay-back.csv