  We present the full panchromatic afterglow light curve data of GW170817,
including new radio data as well as archival optical and X-ray data, between
0.5 and 940 days post-merger. By compiling all archival data, and reprocessing
a subset of it, we have evaluated the impact of differences in data processing
or flux determination methods used by different groups, and attempted to
mitigate these differences to provide a more uniform dataset. Simple power-law
fits to the uniform afterglow light curve indicate a $t^{0.86\pm0.04}$ rise, a
$t^{-1.92\pm0.12}$ decline, and a peak occurring at $155\pm4$ days. The
afterglow is optically thin throughout its evolution, consistent with a single
spectral index ($-0.584\pm0.002$) across all epochs. This gives a precise and
updated estimate of the electron power-law index, $p=2.168\pm0.004$. By
studying the diffuse X-ray emission from the host galaxy, we place a
conservative upper limit on the hot ionized ISM density, $<$0.01 cm$^{-3}$,
consistent with previous afterglow studies. Using the late-time afterglow data
we rule out any long-lived neutron star remnant having magnetic field strength
between 10$^{10.4}$ G and 10$^{16}$ G. Our fits to the afterglow data using an
analytical model that includes VLBI proper motion from Mooley et al. (2018),
and a structured jet model that ignores the proper motion, indicates that the
proper motion measurement needs to be considered while seeking an accurate
estimate of the viewing angle.
