You have to really adjust for inflation, and that is why it is so hard to compare the OT to Harry Potter. You can compare the PT movies to Harry Potter cause they came out in the same years, but the OT movies adjusted for inflation are in the top 12 of all-time.

All-Time Domestic Gross (Adjusted Inflation) source: boxofficemojo.com

#2 - Star Wars 1.17 Billion

#12 - Empire Strikes Back 646 million

#14 - Return of the Jedi 618

Those numbers are mind boggling compared to todays numbers. Even if you take away the SE & Rerelease numbers from the movies, they still gross well over any movie today.