Wouldn't worry about it JB - I think it's down to personal metabolism/physical make up etc... Also a lot depends on how much exertion you put in compared to others... I used to do exercise classes at our gym and would finish with sweat dripping (no, pouring down from myself) compared to all the girls - then one day I decided to watch and see why that was - seems if an aerobics class called to kick your leg, I kicked and kicked hard and when I stopped to watch everyone else they were just lifting their leg up and down...
I think it's an efficient metabolism too (personally, I know others would disagree with me) since more sweat = higher efficiency at cooling down body heat.
I tend to be very hot blooded and am always the one wearing a t-shirt in winter cos I'm just too warm.. so prob need more sweat to cool down - maybe you're like that too?