Current TV whitespace regulations mainly benefit rural areas where large amounts of TV whitespace exist. Thus, the spectrum scarcity problem is yet to be addressed in urban locations, where it is most experienced. To further improve the spectrum efficiency, a new framework for cognitive radio network operation is presented, which can coexist with current broadcast TV networks. Through geographical evaluations based on distribution of TV towers and population dynamics, it is shown that by leveraging the TV viewership statistics, 5.6-7.7-fold increase in available channels can be provided to mobile users in populated areas such as New York City. Furthermore, daily dynamics of TV viewership can be exploited to provide up to 96 MHz additional bandwidth during prime time and 162-228 MHz additional bandwidth during non-peak hours. The additional TV spectrum can provide additional channel capacities in both rural and urban areas. To the best of our knowledge, this is the first work that analyzes TV whitespace availability based on TV viewership statistics in space and time.