Average Plant Growth Measurement

A middle school science class conducted an experiment to measure the height of various plants over a month. The results were recorded in a line graph. The graph shows the following data:

• Week 1: 5 cm
• Week 2: 7 cm
• Week 3: 10 cm
• Week 4: 12 cm

Based on the graph, how much did the plant grow on average per week over the four weeks?