Source: I will resolve this based on the "Domestic Theatrical Market Summary for 2024" from The Numbers: https://www.the-numbers.com/market/2024/summary
To be precise, on July 2nd (to give ~24 hours for results to come in), I will check that website, and will resolve based on the number that is listed. [1]
For reference, according to the Wayback Machine, on July 12th the 2023 page listed a total (cumulative domestic) box office gross of: $4,734,440,650. That's the equivalent number that I will use (although from 10 days later—it's the closest date logged).
The current 2023 page lists $8,946,159,192 for the total cumulative gross of 2023.
If any aspects of resolution are unclear, please ask.
[1] This will may not exactly correspond with the box office gross from the first half of 2024 (it depends on how fast the results are updated), but it's a reasonable approximation, and I wanted to ensure there was a consistent rule for resolution.