The pie charts provided illustrate two major changes in the use of modes of transport to a certain university between 2004 and 2009

The pie charts depict how students utilized a range of transport to commute to a college from 2004 to 2009.
Overall, The proportion of cars witnessed a significant drop during the remainder grow noticeable in five years. The highest proportion of users of the vehicle was the bus.
Looking at the pie graph 2004 in more detail, the percentage of buses stood at 33%. The rate of cars was more than a half of graph. The rate of the three-vehicle remainder less than a fifth of the graph was 9% of biking, 4% of using a train, 3% of walking.
Turning to the pie graph 2009 in more specifically, the percentage of buses saw a dramatic development from 33% in 2004 to 46% in 2009. However, the rate of cars fell over half at first remain 23%. The proportion of bikes slightly grow from 9% to 16% in 2009. The proportion of walking and train had minimal changes 1% and, 2% respectively.