“We're descending toward Hill Valley, California, at 4:29 pm, on Wednesday, October 21st, 2015.” – Doc Brown in the movie “Back to the Future II” released in 1989.

From the Universal Pictures official site: Life often imitates art, but rarely does it arrive right on schedule! Fans of Back to the Future are well aware of the powerful significance of dates, and they’re now especially focused on October 21st, 2015, the day that Marty McFly first set foot in Hill Valley, 30 years in the future!

Key Stats:

The U.S. population clock is based on a series of short-term projections for the resident population of the United States. This includes people whose usual residence is in the 50 states and the District of Columbia. These projections do not include members of the Armed Forces overseas, their dependents, or other U.S. citizens residing outside the United States.

U.S. and World Population Clock

More Stats:

Each year, the Census Bureau's Population Estimates Program (PEP) utilizes current data on births, deaths, and migration to calculate population change since the most recent decennial census and produce a time series of estimates of population, demographic components of change, and housing units. The annual time series of estimates begins with the most recent decennial census data and extends to the vintage year.

165,931,202 - Population as of July 1, 1955

237,924,000 - Population as of July 1, 1985

News Release Number: CB14-TPS.90: Census Bureau Projects U.S. and World Populations on New Year’s Day

320,090,857 - Population as of January 1, 2015

321,195,023 - Population as of July 1, 2015

From Table 3. Projects of the Population by Sex and Selected Age Groups for the United States: 2015-2060. Population projections are estimates of the population for future dates. They are typically based on an estimated population consistent with the most recent decennial census and are produced using the cohort-component method. Projections illustrate possible courses of population change based on assumptions about future births, deaths, net international migration, and domestic migration. In some cases, several series of projections are produced based on alternative assumptions for future fertility, life expectancy, net international migration, and (for state-level projections) state-to-state or domestic migration.