Q:

Source for up-to-date values of Mars' standard gravitational parameter

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?

A:

The most up-to-date is from the work in this paper, due to be published in July 2016. The actual numbers can be found in this large file, for which the number you seek is the second number in the file, and its uncertainty is the third number in the file. (The rest of the numbers are the higher order terms of the gravity field. You can find a detailed description here.)
Here are those numbers, copied and pasted from the file, in units of $\mathrm{{km}^3/s^2}$:
4.2828372854187757e+04, 1.6202815226760665e-05

I would write that a little more accessibly as $42828.372854(16)\,\mathrm{{km}^3/s^2}$, where the two digits in parentheses is the $1\sigma$ uncertainty in the last two digits of the value. Note that if you need that many digits in GM, then you also need a higher order gravity field to get the real answer.
The GM of Pluto is best determined by observations of it and its moons over long periods of time. The value I found in this recent paper is $869.6\pm 1.8\,\mathrm{{km}^3/s^2}$ (where the error is about $0.2\%$). New Horizons may have improved that some, by virtue of better locating Pluto and its moons. But I suspect not by much.

