census bureau in lisa sturtevant from george mason university. what do these maps tell you in terms of the direction of the country? >> guest: discount areas, metro growth rates are indicative part of an emergence. i think about these maps when i look at the mobility rate. residential mobility is the rate of folks in that one year to the next and for a long time, rates from the decline. in 2012 the mobility rate picked up for the first time and was driven by the state to state migration. what that means is people are able to move and they move for jobs. the population growth is highly concentrated in the energy sector, counties in matcher areas. >> host: what government programs affect population growth? >> guest: right now, population growth is driven by deployment less of a government programs. for the population estimates and are set as government programs is the fact that 80% of federal grants, states and localities are driven by a formula that includes population estimates. so if you're not orange county the population, that may be problemat