Denver’s next mayor could be a businessman whose household brought in $1 million-plus in 2021 or a retiree who reported no income that year. The job also could be filled by any of the several candidates who reported six-figure incomes over the past five tax years from a variety of sources: banking, entrepreneurship or serving as chief executives. Whoever wins will earn nearly $190,000 a year — or possibly more, after the City Council adjusts officials’ salaries in coming weeks — to lead a city of 711,000 people and a municipal government with more than 14,000 workers. The Denver Post asked each of the 17 candidates on the ballot for copies of their tax returns for 2017 through 2021.