UC3844: Active life cycle of UC3844 ( Upto how many years UC 3844 Available Active)

Dear Sir,

We are using UC3844 PWM Control IC in our various SMPS cards.

we want to use same IC in one of our new development Product for that we want to know that active life cycle of UC3844 IC means upto how many years UC3844tab  available in market actively so we can use it in our new design.

Regards,

Chetan patel