How many percent plc use in industrial?

depend upon 

one hundred percent

Almost100% now in new and even old industrial equipment.

In Industry, PLC actually majorily replaced:

1) Relay Logic

2) Dedicated Control Cards / Systems.

As far as Relay Logic is involved PLC must replace it100%.

As far as Dedicated Control Cards / Systems not more than70% to90%.

75 percentage

Eighty percent Of PLC is USed in Industries Now a Days

3 percent

DEPEND UPON I/O INTEGRATION AND INDUSTRY REQUIRMENT

Scemens PLC,( ON and OFF control systen PLC).