Depletion time describes the length of time it takes to use up

50% of a mineral reserve.
60% of a mineral reserve.
75% of a mineral reserve.
80% of a mineral reserve.

The graph shows the number of employed workers in the united states in nonfarm jobs from 2008 to 2013. the best conclusion that can be drawn from the graph is that the number of nonfarm jobs remained consistent over time. started going down in 2008. went up every year since 2008. started going down in 2010.