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`Imaka is a ground layer adaptive optics (GLAO) demonstrator on theUniversity of Hawaii 2.2m telescope with a 24'x18' field-of-view, nearly anorder of magnitude larger than previous AO instruments. In 15 nights ofobserving with natural guide star asterisms ~16' in diameter, we measure medianAO-off and AO-on empirical full-widths at half-maximum (FWHM) of 0''95 and0''64 in R-band, 0''81 and 0''48 in I-band, and 0''76 and 0''44 at 1 micron.This factor of 1.5-1.7 reduction in the size of the point spread function (PSF)results from correcting both the atmosphere and telescope tracking errors. TheAO-on PSF is uniform out to field positions ~5' off-axis, with a typicalstandard deviation in the FWHM of 0''018. Images exhibit variation in FWMM by4.5% across the field, which has been applied as a correction to theaforementioned quantities. The AO-on PSF is also 10x more stable in timecompared to the AO-off PSF. In comparing the delivered image quality to proxymeasurements, we find that in both AO-off and AO-on data, delivered imagequality is correlated with `imaka's telemetry, with R-band correlationcoefficients of 0.68 and 0.70, respectively. At the same wavelength, the dataare correlated to DIMM and MASS seeing with coefficients of 0.45 and 0.55. Ourresults are an essential first step to implementing facility-class, wide-fieldGLAO on Maunakea telescopes, enabling new opportunities to study extendedastronomical sources, such as deep galaxy fields, nearby galaxies or starclusters, at high angular resolution.