C172 pilot reported erroneous airspeed indications after take off resulted in return to departure airport

Narrative

I was taking a friend from ZZZ to ZZZ1 for dinner. I did a thorough preflight and there were no indications that there were any blockages in the pitot static system. We departed ZZZ on a left crosswind departure. I performed my normal call-outs verifying 'airspeed alive'; and 'engine gauges in the green'. Everything looked normal.After rotation while I was climbing visually at my normal Vy pitch; I cross checked my airspeed indicator (ASI) and it read 60 knots (versus the target of 78). I pushed the nose forward to gain airspeed; but the ASI remained at 60. This seemed odd to me as we were not at a particularly high angle of attack. I looked outside to verify my flaps were retracted. Then as I continued climbing the ASI slowly decreased to below 45 and eventually 0. Obviously at this point I knew I had an erroneous indication; so I declared [a priority] and requested a return to landing.Knowing I would need to land with no ASI; I used known power settings and cross checked my iPad briefly to make sure my ground speed was in the ballpark (90kts ground speed - 10kts tailwind = target 80kts). I did a short approach back to [Runway] XXL trying to keep my airspeed up and after floating down the runway a bit I dumped my flaps when I was confident I was somewhere in the white arc. We landed uneventfully. The aircraft has been grounded to have its pitot static system inspected.