So, about 27% have been cast already unless turnout is even higher than 2020.
Total ballots cast for each of the past 8 US presidential elections:
2020: 158,481,688
2016: 136,787,187
2012: 129,139,997
2008: 131,406,895
2004: 122,349,480
2000: 105,594,024
1996: 96,389,818
1992: 104,600,366