Welcome to this half-dead forum
Do you have 22 players? If yes, how many of them are usually injured?
I think this is individual, my team doesn't have much injuries problem, usually i have 0-2 injured players, but when injury period comes then i have sometimes 5-6 of 22 available players (~25% of team) .
I think form personal xp that injury rate isn't that high compared to real life football. Yes, no one likes injuries, but remember how many real teams have problems with injuries. If you don't know, please check this out;
EPL Injury table
English Premier League Injury Table - PhysioRoom.com
Look at top injury-affected teams:
Newcastle: 12/31 (12 injured of 31 available players in squad) (39%)
Everton: 10/24 (42%)
ManUtd: 8/27 (30%)

And what is precentage of your/our injured players in team? In mine currently under 10% of players are injured.