An analysis of cosmological data from the Planck satellite gives a value for the Hubble constant of 68.0 km s−1Mpc−168.0\text{ km s}^{-1}\text{Mpc}^{-1}68.0 km s−1Mpc−1. What is this value, written to 2 significant figures, in s−1\text{s}^{-1}s−1? (Take 1 pc=3.09×1016 m1\text{ pc} = 3.09 \times 10^{16}\text{ m}1 pc=3.09×1016 m)
