Wikipedia currently gives the standard gravitational parameter of Mars as:
$$ GM_{Mars} = 4.2828(9) *10^{13} (m^3/s^2)$$
The (9) is the uncertainty of the last digit, so it works out to about 210ppm (parts per million) which is astronomically large (pardon the pun).
note: the Standard Gravitational Parameter of a body is the product of the gravitational constant G and the mass M of the body. Orbital data of satellites (natural and artificial) depends on the product of the two, so it can both be measured to higher precision (accuracy?) and it's actually just the thing you need to calculate the next mission's trajectory.
With all of the orbiting satellites and landers, I'm guessing there are updated values with more digits. This answer is helpful, but while the linked page for solar system satellites ssd.jpl.nasa.gov/?sat_phys_par lists GM, a similar page for planets ssd.jpl.nasa.gov/?planet_phys_par lists M in kg:
$$ M_{Mars} = 0.641693 ± 0.000064 *10^{24} (kg)$$
That value still has an uncertainty of 100ppm, and if one tries to recover GM by multiplying by Gravitational constant G, the uncertainty there is still also high - about 47ppm.
My question: What is a good source for the most up-to-date value of Mars' standard gravitational parameter which also gives the experimental uncertainty of the value?
Bonus: The same Wikipedia article gives a value for pluto of:
$$ GM_{Pluto} = 8.71(9) *10^{11} (m^3/s^2)$$
which has an uncertainty of 1%! (10,000ppm). Has the recent New Horizons fly-by trajectory and extended imaging been enough to improve on this value?