The following PDF contains a series of tables detailing Japanese homeland casualties due to air raids and naval artillery strikes during WWII. The tables are translated from:
Overall Report of Damage Sustained by the Nation During the Pacific War.
Economic Stabilization Agency, Planning Department, Office of the Secretary General, 1949.
The original document, 「太平洋戦争による我国の被害総合報告書」, can be viewed at the website of the National Archives of Japan – Digital Archive (国立公文書館・デジタルアーカイブ).