However, if you remember the total number (or can approximate it) and it's really important to you to know how many ads AdBlock has ever blocked for you, you can set AdBlock's counter to start at that number instead of 0 after a reinstall. Here's how.
Open the Chrome Extensions page (Chrome menu > More Tools > Extensions or open a new tab and enter chrome://extensions).
Enable Developer Mode in the upper right corner of the page.
Find AdBlock in the list of extensions.
To the right of "Inspect views," click background page. The Chrome Developer Tools window opens.
Select the Console tab.
Enter the following command, where "x" is a valid integer: Prefs.blocked_total = x