The Office for Rail Regulation have published the station usage figures for the year ending 31 March 2020. Overall they show a 1.1% decline in rail usage nationally, although this can can probably be attributed to the early days of the pandemic.
Locally our stations showed a greater fall in numbers. Longfield fell from 299,510 passengers the year before to 292,815 in 2019/20 (this is half the published "entries and exits" figure). Meopham fell by over 5,000 passengers to 163,550 and Farningham Road fell by 6,000 to 99,492. All stations showed particular decline in season ticket usage, but it still makes up 50.3% of Longfield's passengers with similar percentages for Meopham and Farningham Road.
For a history of local passenger numbers over time, see the Railways history page.