Final answer:
Food prices during the given time period cannot be determined accurately.
Step-by-step explanation:
The period during which food prices increased about 20% per year is not mentioned in the given information. However, it is stated that food spending by U.S. households declined between 2006 and 2009. Therefore, it can be inferred that food prices did not increase significantly during that time period. Unfortunately, there is no information provided about the year when food prices had almost no increase.
Regarding the time period when prices of other items increased faster than food, no specific information is given in the provided text.
Based on the given information, the answer to each question cannot be determined accurately.