I normally use

http://msdn.microsoft.com/en-us/library/ms186265(SQL.90).aspx

sp_trace_setevent (Transact-SQL)

that lists events with the last event number 202 with 10 of them reserved, total number 171. The question was how many of the events are available using Profiler, so I was not sure if Profiler as a user interface lists all evants available for the traces. Since the question explanation is to query sys.trace_events then I think the trace events should be counted