how to track number of visitor in a website for past 1 hour?

Question

Hi sir,

 

          I need to track the number of visitor hit my website for the past 1 hour. How can i implement this?

 

[For example:  I need to track my website http://www.sample.com for the past 1 hour. I need to know how many users can access my url for the last 1 hour]

 

Kindly give me the solution for this problem.,