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Posted: Wed May 31, 2023 8:41 pm
How can I create a new series that represents the annual sum of GDP for each quarter, given a quarterly GDP data series from 1981Q1 to 2023Q4? For example, the values from 1981Q1 to 1981Q4 should all be the sum of the GDP for the four quarters of 1981, and the value from 1982Q1 to 1982Q4 should be the sum of GDP for the four quarters of 1982.