Where can I see the exact row count of a table in pgAdmin III?
Two lines below the estimate you highlighted we can see:

Rows (counted)  not counted


Right-click and choose Count from the context-menu to get the current count right there. Be aware that the count is only accurate in the moment it is taken.
pgAdmin does not count rows in big tables (because that can be expensive) unless it's told to do so. There is a setting in the Options:

Count rows if estimated less than [2000]


Replace the default 2000 if you want a different limit. Details in the manual here:

http://www.pgadmin.org/docs/1.20/options-browser.html