Acceleration and dynamics of energetic electrons in the outer Van Allen radiation belt can be influenced by cross-energy coupling among the particle populations in the radiation belts, ring current and plasmasphere. Waves of different frequencies have been shown to play a significant role in these interactions. We analyze more than 10 years of measurements of the four Cluster spacecraft to investigate propagation properties of whistler-mode waves in the crucial regions of the Earth's magnetosphere. We use this unprecedented database to determine the distribution of the wave energy density in the space of the wave vector directions, which is a crucial parameter for modeling of both the wave-particle interactions and wave propagation in the inner magnetosphere. We show implications for radiation belt studies and upcoming inner magnetosphere spacecraft missions, and we also show similarities of the observed whistler-mode waves with results from the magnetosphere of Saturn collected by the Cassini mission.