How to know how much data Opera is downloading for viewing a web page by using the progress bar

I have always wanted to know how much data my browser is downloading , for me to view a particular web page .I always use opera for browsing , one of the reasons being it tells me the amount of data downloaded .To view this data, when a webpage is loaded, do the following,

Open opera (This is for version 9).

Go to Tools > Appearance.

Then go to the Toolbars tab and then you will be able to see a Progress Bar dropdown box.

By default it is set to Simple.

Select pop-up at bottom from the dropdown list and click the OK button.