  One of the most crucial yet poorly constrained parameters in modelling the
ionizing emissivity is the escape fraction of photons from star-forming
galaxies. Several theoretical and observational studies have been conducted
over the past few years, but consensus regarding its redshift evolution has yet
to be achieved. We present here the first non-parametric reconstruction of this
parameter as a function of redshift from a data-driven reionization model using
a Gaussian Process Regression method. Our finding suggests a mild redshift
evolution of escape fraction with a mean value of $4\%,7\%,\sim10\%$ at
$z=2,6,12$. However, a constant escape fraction of $6-10\%$ at $z\gtrsim 6$ is
still allowed by current data and also matches other reionization-related
observations. With the detection of fainter high redshift galaxies from
upcoming observations of JWST, the approach presented here will be a robust
tool to put the most stringent constraint on escape fraction as well as
reionization histories.
