Let say: a shop open in March, and it has provided service for 2 month.

Question: Is there any word means "duration since starting service" to present this 2 month?

I have some ideas but seem not appropriate: "Period for business", "Period for service", "duration since starting service" etc.

Actually, I am confused to present this idea. Hope you can understand what I am saying...

Thx for reply.
The shop has been (trading)/(open for business) for two months
Many stores will say "Established".

So: Established (Est'd) March, 2008.
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Est'd can mean the date the Company was set up - it didn't necessarily trade or provide services from then.
I set up one of my Companies in September 2003 - so it was Established Spetember 2003
but we didn't start trading until January 2004
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thank you so much