Depends upon the service center your application goes to and the specific type of application you are submitting. You can research processing times here:
https://egov.uscis.gov/processing-times/
Current processing times listed are:
CA: 3 to 5 months
National Benefits Center: 4 to 6 months
Nebraska: 3.5 to 5 months
Texas: 4 weeks to 5 months depending upon type of I-131 request
Vermont: 5.5 to 7.5 months