Te 510 2009 Best Front Sprocket

Hi all, I'm going to replace the final transmission, the previous owner installed a 12 teeth sprocket but I think is too short...

I'll use the bike in a mix of road and off-road, which could be the best sprocket choice?
Thanks

13 was the factory size and more appropriate for what you do. The 12 is better suited for trail use.

I was wrong!
The actual sprocket is 13, and I'm thinking about a 14 or maybe a 15...

Actually on road I'm contantly searching for the 7° gear, and the best speed/rpm ration on asphalt to avoid to go too high with the motor is around 80 km/h

Yes go up by all means for road use