"The Median Amazon Employee's Salary Is $28,000. Jeff Bezos Makes More Than That in 10 Seconds" - Time
Not sure why part time and seasonal workers don't count since that's often the only way to even start working at Amazon.
Same for switching between seasonal jobs; if I'm working for Sunshine Ranch as a ranchhand April through September, and I'm working for Powder Bowl Ski Lodge as a custodian October through March, those two companies would need to be taxed proportionately.