What's the difference between "fluctuate" and "teeter"?
Fluctuate = vary with time. Think graph, chart.
Teeter: (1) go back and forth (between the same two things/values). Think teeter-totter. (2) be on the verge of something - the current little wiggles/variations are likely to soon change into a huge plummet. Think cartoon character balanced on the edge of the cliff.