The following table contains the most recent observations (December 04, 2023) from FRED* on M2 and several series relevant to the measurement of alternative monetary aggregates.
Series Value (in billions)
M2 Money Stock $20872.7
Small-denomination Time Deposits $1033.8
Retail Money Funds $1716.7
Demand Deposits $4991.9
Other Liquid Deposits $10889.6
*Real-time data provided by Federal Reserve Economic Data (FRED), Federal Reserve Bank of Saint Louis.
Using the data recorded above, the most recent observation of M1 must be $\boxed{} billion. (Enter your response rounded to one decimal place.)