How to develop KPI for IT department?

Dear Pasun,
A general algorithm to define any KPIs including for the IT department was described here. And for sure, there are some more or less standard indicators that with minor modifications can be applied to any business (listing them below).
Finance:

• IT expense as a percentage of total expense
• IT expense per employee
• Support expense per user

Customers:

• User request response time
• The number of critical problems reported by user
• Business System Utilization

Internal:

• Mean Time Between Failures (MTBF)
• Mean Time to Repair (MTTR)
• Availability (uptime)
• Downtime related to security issue

Learning & growth:

• The number of returning problems
• Restore success rate

Additional note: you can find more information about IT KPIs + example of the Balanced Scorecard for IT in this new article.