I think the whole philosophy of the grading:price ratio has changed, certainly since the 60s. Back then you had 3 top grades that were closer together : UNC: a state rather than a condition EF: today's AUNC, with a price to match, VF: today's GVF or even NEF and closer to EF in value than now. Then you had F, trailing a long way behind, the "minimum acceptable condition" for collectors Now, due to international pressures? collector influence? dealer practice? all these and more?, you have a situation where the 4 top grades are more evenly spaced, and so are the values. Which effectively means that UNC and F should be the same grades as they were (though in some lists F covers a multitude of sins..), but EF has dropped quite a lot, and VF dropped to a lesser extent. I'm not sure how typical this is, but these are the values (Seaby/Spink) for a 1904 halfcrown in 1966 and 2012 : F 2:50 VF 5:00 EF 12:00 (no UNC value listed, but one would guess that it would have been probably £15-£18) F 65:00 VF 300:00 EF 925:00 UNC 2500:00