Tyler, a single taxpayer, generates business income of $3,000 in 2016. In 2017, he generates an NOL of $2,000. In 2018, he incurs another NOL of $5,000. In 2019, he generates a modest business income of $6,000 and then in 2020, the COVID-19 pandemic results in an NOL of $13,000. Assume that in all years, Tyler adopts the NOL treatment that results in the earliest and greatest refund. Provide a chronological analysis of Tyler's treatment of NOLs through 2020.