(too long for a comment, this answers why barycenter data is available for a much longer time span than planet center data)
When NASA computes planetary positions, they treat each planet and its moons as a single point mass (the barycenter of the planet and its moons). They compute these positions +-15000 years from now.
For most planet systems, the barycenter is very close to the planet center (Mars' planet barycenter is only a few inches from Mars' system barycenter because Phobos and Deimos have such little mass-- for the moonless Mercury and Venus, the system barycenters and the planet barycenters are the same).
They then compute the locations of the moons and the planet's center itself. These calculations are done for a much shorter period of time.
Therefore, you can compute the location of the barycenter of Jupiter and its moons for +-15000 years, but the actual barycenter of Jupiter itself for a much shorter period of time, even though Jupiter is massive enough that its own barycenter is very close to the barycenter of Jupiter and its moons.