Fuel Gauge never reads full

[Overdrive]

Hey, everyone. This is an issue I noticed right off the bat with my '97. When I first got it I went about filling the tank, as it was reading between 1/4 and empty. I let the pump work until it shut itself off, and this was so long ago that I can't recall how many gallons I did actually pump, but the point being when I got back in the car and fired it up, the fuel gauge only came up to just about halfway between 3/4 and full.

So far I've filled the tank twice, and the gauge still only goes as high as that with no noticeable improvement. It does take a decent amount of miles before it moves from that indicated spot, but it has never read full for me, so to be safe I have never let the gauge go below 1/4 again, as I can't trust the gauge. Now the car did sit at the place I purchased it from for about 5 years or so and was probably only started to move it from one space to another on the lot during that time, possibly the occasional test drive of any interested folks, and probably also had that low level of fuel in it for that long period of time, but my wonder is whether this is a problem of 14 years of age and the gauge just not reading as well as it did back in 1997, or if there could be a different problem? Finally, is there some way of adjusting/re-calibrating the gauge so that it will read full when the tank is indeed full? If there's any other information on the matter that anyone needs I'll do my best to provide that for you. Thanks for any help, insight, and/or advice provided, everyone.