Taxation systems are usually modeled in such a way that they take into consideration the social welfare of the citizens. The government and other policy makers have the responsibility of ensuring that the system takes into account the needs of the citizens. The bottom line is that taxation should foster equal distribution of resources. The rate of taxation is usually arrived at after several considerations have been made. The rates are not fixed as they depend on the various economic changes. The issue of how taxation should be distributed among the different economic classes is yet to be addressed.
Whenever economic turbulence increases, the policy makers adjust the taxation rates in an effort to stabilize it.