How to explain the prediction of opreg command for total factor productivity(TFP)

[owen wang]

I use "opreg" command to estimate the OP method total factor productivity with a panel of arould 10000 firms and 8 years.After the estimation, I used "predict tfp" to get the result of tfp for each firm . The result is between 1 to 5, 90% are between 1.3 to 3.5, is the result reasonable? Is tfp predicted here is the growth rate of tfp of each firm? And how should I explain the exponentiated tfp?
Thanks a lot!