As per Books Online:
For per-second counters, this value is cumulative. The rate value must be calculated by sampling the value at discrete time intervals. The difference between any two successive sample values is equal to the rate for the time interval used.
So what you're seeing there is the cumulative (total) number of deadlocks that you've had.
If you want to see the number per time interval, then, as per BoL, you need to query that at multiple times and take the difference to see the number of deadlocks in the period of time between the two samples.
If you want to investigate the deadlocks further, switch traceflag 1222 on (not 1204, not 3605). That will result in a deadlock graph been written to the error log every time a deadlock occurs. Post the result of that graph here if you want help with the analysis.
DBCC TRACEON(1222,-1)
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability