YEAR, not periodic
QUARTER, period 4
Date. Format: "QQ YYYY"
Error for Quarterly_index from SEASON, MOD_2, MUL EQU 4
Seasonal adjusted series for Quarterly_index from SEASON, MOD_2, MUL EQU 4
Seasonal factors for Quarterly_index from SEASON, MOD_2, MUL EQU 4
Trend-cycle for Quarterly_index from SEASON, MOD_2, MUL EQU 4