Intel processors support multiple technologies to optimize the power consumption. In this article, we provide an overview of p-states (optimization of the voltage and CPU frequency during operation) and c-states (optimization of the power consumption if a core does not have to execute any...
My guess is that Core Cx Residency refers to the percentage of time(?) the CPU is in this state, saving power. The higher the percentage for these values the more power is saved (potentially).
Your conclusions about C-states, will be best drawn by the 4th (average) column. The current/min/max values are the least valueble. Only on average you will see each core how much time has spended in each state.
Take for example one core (0 for instance) and add the avg(4th) percentage from each Cx state. It sums up =100
Do this for any core, on any time and always =100