I noticed the same thing its wierd. But i believe certain levels are better for certain resources so idk try looking where gold starts compared to Diamonds and dig there I think youll find more.
EDIT: Gold starts at 32 so try digging 12->32 somewhere in there to get more gold
The numbers we used were using over 9000 generated chunks, compared to the wiki's 3000, or outdated generation.
Either way, the difference is far smaller than the variance introduced by chance in what you find. For any practical measurement, their density is the same, and finding more of one or the other is pure randomness.
There are certain types of large cave systems that contain a lot of gold. They usually will have very few level 10 lava lakes, and don't reach high enough to get to the surface. Level 14 mines have a higher chance of hitting them than level 12 mines. In one of them I found about 45 gold ore in that one cave. The minus to them is that they don't have many diamonds or lapis lazuli.