We report a measurement of the fraction of top quark pair events produced via gluon-gluon fusion in $pbar{p}$ collisions at $sqrt{s} = 1.96 ~rm TeV$ in lepton+jets final states using the full RunII data set corresponding to $9.7 ~rm fb^{-1}$ of integ
rated luminosity collected by the DO experiment. We utilize a boosted decision tree to distinguish top quark pair events produced by $qbar{q}$ annihilation and $gg$ fusion. We perform a template fit to extract the $tbar{t}$ production fraction via $gg$ fusion and find $f_{gg} = 0.096 pm 0.039 ~(rm stat.) ~^{+0.077}_{-0.062} ~(rm syst.)$.
