I don't think so there is a standard benchmark for hike. It is based on various factors
1. Company profit.
3. Individual employees contribution
So on. The minimum hike can be to meet the employees standard of living against the inflation.
11th May 2016 From India, New Delhi
I echo Vivek. Please decide as per your budget. As you have already mentioned that your firm is a startup. It would be best if you don't try to compete in terms of pay.
Still if you really wish to, please buy a salary report from Kelly Services or any other top HR consultancies. That would give you quantified data that you can refer, rather than collecting it randomly.
Any job site can share the pay for similar jobs that you are hiring for. You hiring consultants can easily share what your competitors are paying, but then that is not a very trusted source.
Identify how do you look forward to enrich each role as you revise the salaries. Assuming that you have strong measures in place, can you consider pay-for-performance strictly along with the basic and other components?
Looking forward to hear from you.
11th May 2016 From India, Mumbai