That is incredible!
Years ago, I saw a similar statistic for the amount of lead bullets fired on the British army retreat on “The Battle Road” after the fight at Concord & Lexington. Not explosive shells, of course, but lead bullets. The amount of lead in the air was incredible.
A few years ago, I read a really good book about Verdun. There were stories of whole battalions of French infantry being sent forward to reinforce the line. 500 men would set out. Less than 10 would reach their destination a mile away. They still find bones on the battlefield.