The PDC world rankings are calculated using prize money earned from ranking events over a rolling two-year period.
World number two Littler collected £200,000 for his victory in Blackpool, taking him above the £1.5m mark overall.
He is now within £300,000 of world number one Humphries’ total of just under £1.8m.
Because Littler did not play in any major events during 2023, any prize money he makes until the World Championship in December will be pure profit for his tally.
Humphries, meanwhile, won three big televised titles towards the end of 2023 before his World Championship final victory against Littler in January 2024.
He will be defending in excess of £400,000 of his prize-money total before the World Championship.
Michael van Gerwen, who is third in the world rankings behind Humphries and Littler, has won close to £740,000 over the past 24 months.
