Which one of these best illustrates time series analysis?

1. A firm's profit margin has been 4.6 percent, 4.9 percent, and 4.7 percent over the past three years.

2. A firm has a profit margin of 5.2 percent as compared to 5.1 percent for its nearest competitor within the industry.

3. A firm has a gross profit of 64 percent compared to a 61 percent for firms both in its industry and its geographic area.

4. A firm has a profit margin of 4.6 percent as compared to its industry average of 5.5 percent.