Answer:
"The average cost of groceries has increased 10 percent since last year" statement from a newspaper article refers to the consumer price index (CPI).
Step-by-step explanation:
A Consumer Price Index "calculates increases in the price level of a weighted average consumer goods and services market basket purchased by households". It is usually calculated and published on a monthly and yearly basis by a country's Bureau of Economic Analysis and Statistics.
For an instance the Consumer Price Index for "All Urban Consumers (CPI-U)" rose 2.0 per cent from April 2018 to April 2019, the largest increase over the year since the 12-month period ending November 2018.