50%? do you mean you get nervous? feel you heart beating at about 200 beats a second, hands shaking, cold sweat? i know i do. i always do. and i get on stage about 50% MORE than in the practice room.
how come? it's easy. it's actually good to feel nervous - it gets all your senses working at 200% - you can feel better the audience, and, most important, you can transmit them better what you feel. don't even try to control your heart rhytm or your hands' shaking - it's not gonna work (i tried pills, and it's no good). all you have to do is try to control your head by not allowing any thoughts not regarding what you're playing - keep playing the work in your mind and think of nothing else. and get on stage as often as possible (for about a year, i i got on stage at least weeky, even if it meant repeating works i had played before on the same stage), and everytime you'll see it gets better: you feel nervous before going on stage (worst is the last hour before a recital - at least for me it is), but once you start playing, your heart rhytm is ajusted in a matter of seconds to the rhytm of what you're playing, cold sweats go away, hands stop shaking, and so on.
One more thing - at least for a while, it would be best if you would put the first work in your recital to be something slow.
and never, ever, not under any circumstances, when you're playing something, do not think ahead - "oh, that nasty passage is coming...", you rush, and won't sound to good. on stage play in your head exactly what the hands are playing at that moment, and always play in your head everything - dynamics, staccato, legato, as much as possible - helps the hand.
try this, you'll see, it works like a charm - worked for me and works for my students.