In that case, you are now taller than Yao Ming. The subject of the sentence is your height, and you said it grew 'above'. Therefore the only valid interpretation is that your height is now above Yao Ming's. For it to be interpreted the other way, you would have had to say "My height grew _faster_ than Yao Ming's last year", or "My height _growth_ was above Yao Ming's last year". My point is that people can interpret things any way they want, but that doesn't mean their interpretation is valid.
Hah, we're getting off topic. You're right, phrasing it that way leads to multiple interpretations whether correct incorrect. When I read the title originally, I was thinking "total profit" instead of relative. Whether intentional or not, I think the title could have been worded better.
