My 'Buffer cache hit ratio' is constantly over 2600.00

I am setting up some alerts on my company's SQL Server Database. All of the documentation I read tells me that the'Buffer cache hit ratio'  should be 100 or less as it is a percentage. Mine is constantly 2500.

Please can somebody explain about the 'Buffer cache hit ratio'  and tell me why mine doesn't seem to follow the rules?

Thanks

Les