If your data is in Sheet1 (column B city names and column M times), and
On Sheet2 in Cell A2 is the City name you want to use,
enter this formula in cell B2 on Sheet2:
This will return the number of responses less than 11 minutes in the city identified in A2.
You will need to change the ranges to match the data - both the sheet names and the data range - I didn't have 50,000 rows of data!
You probably also want the number of entries for each city, so on sheet2 in cell C2 enter this:
Now in Cell D2 this:
=B2/C2*100returns the percentage of responses less than 11 minutes for the selected City.
If you place the time in cell A3, then change the formula in B2 to:
=SUMPRODUCT((Sheet1!B2:B54=Sheet2!A2)*(Sheet1!M2:M54<A3))Now you can easily change the response time as well as the city name.