Task $3$: Accident frequency

$3$ The table below shows Contritum's accident history over the past $3$ years.

$\backslash$table$[[$Year$,2021,2022,2023],[\backslash$table$[[$Number of$],[$workers$]],1000,1500,2000],[\backslash$table$[[$Number of$],[$accidents$]],90,150,225],[\backslash$table$[[$Number of$],[$hours worked$]],2000000,3000000,4000000],[\backslash$table$[[$Days lost due to$],[$accidents$]],155,225,560]]$

$($c$)$ give me $6$ points What are the possible limitations of the data in this table?