What is the probability that the below-given f(x, y, z) will return 1?

\(f\left( {x,\;y,z} \right) = \;\bar x + \bar y{\rm{\;}} + x.z\left( {\overline {x.\left( {y + z} \right)} } \right)\)

where f(x, y, z) is a Boolean function. (answer upto 2 decimal places)