Dear Vivek,
Your question is like "How long a piece of string should be to tie up a person?" Without knowing details of what type of benefits is the bank providing, what is the attrition rate, etc., even experienced persons cannot give you a figure. hence, more information you can give the better for repople to respond positively.
Kindly see the exchange of views at
https://www.citehr.com/319453-key-learning.html to realise the futility of posting short messages, like your first message.
Have a nice day.
Simhan