How many times is it normal to have stage shifts in sleep?

I had a sleep study done and it said I had 53 stage shifts and no Delta sleep, total sleep time was 394 minutes, REM sleep accountd for 13.1% of that time in two distinct periods; and predominated by stage 2 sleep. The report also said I have prolonged REM latency of 224 minutes.

Can anyone help shed some light on how often "normal" people change states in sleep?

I've already read the page here at dreamviews about the stages of sleep, but I didn't see any clear information on how often it is normal to shift between stages.

Thank you.