I spent three months traveling Europe with a 15 to 16 pound (6-7 kg) pack--that is, when I wasn't loaded up with souvenirs, wine, salad bowls, Turkish killims and alabaster and various other artifacts. Fortunately my eldest son was stationed in Germany with the US Air Force at the time so I could stop off there every few weeks and have him ship my artifacts/souvenirs home. My pack was a convertible travel pack (basically a suitcase with stays and hideable shoulder straps and hip belt), not exactly lightweight.

Base weight of my wilderness backpacking gear (everything but fuel, water, food) is a few ounces over 12 lbs. (5.5 kg).