The graph shows how price (cost) data can be used to show on one graph what commodities are priced more in 2010 compared to the price of the commodity in 2006. This is not easily done, as far as I can determine, because each commodity’s price per unit is given in different unit measurements (e.g. ounces, pounds, etc.) and only one unit measurement is graphable on a single graph. One way around this unit problem is to convert the average price for a year into a percentage of the total of average prices for all years. For example, the total of all average unit prices for gold for the years 2006 to 2010 was $4,391 per ounce so that the average price of gold for 2006 ($598/ounce) as a percentage of the total for all years is 14% (598/4391).
The graph shows that the only commodity price (cost) for any of the commodities that was less in 2010 than in 2006 is the price of natural gas.