How create a graph of profit over time
To create a graph of profit over time, you need data over time. Spreadsheets can only plot graphs of data present in a table, or interpolated between. That means you need a table containing rows for each time point you want plotted, not just the current value.
Numbers can import ‘delimited or fixed-width text files’. If you can find a source for the data you need over time, you can import this into Numbers and plot the data over time.
Create one row for each point in time over a contiguous time period with regular interval and use a line graph, or plot using a scatter graph for non-contiguous/non-regular time (other types cannot be used, see Time as x-axis in chart with Apple Numbers).