I have an exercise log spreadsheet set up in Numbers, and I want to use a bar chart/graph to plot my progress. I set up the tables to extend to the end of the year, so when I plot a chart I end up with a ton of blank area after today's entry.

Is there a way to have the chart only graph the cells that actually have data entered into them, and then extend as new entries are added to the cells in the future?
I've also noticed that although I have set up the chart by selecting the tab for Column B (Miles) with the intention of choosing everything in that column, if I extend the table the graph does not automatically include the new rows. Is there a way to make this happen?