On Data-Z most demographic information comes from the American Community Survey (ACS) of the U.S. Census Bureau, and consistently reports the one-year estimates for demographic data instead of the five-year estimates. According to the Census Bureau, one-year estimates are less reliable but more current than five-year estimates. For more information on the differences see this article: When to Use 1-year or 5-year Estimates.
Unfortunately, there will be no release of any standard one-year estimates for 2020. Due to the impact of the COVID-19 pandemic, instead of providing the standard one-year data products, the Census Bureau released experimental estimates from the one-year data. Data users should not compare 2020 ACS one-year experimental estimates with any other data.
Due to the lack of standard one-year estimates for 2020, Data-Z has reported the five-year estimates for that year. Users should be aware of this anomaly. When using five-year estimates, the Census Bureau does not recommend using them with one-year estimates for several reasons. Because ACS variables and geographies may change over time, comparisons should always be made with caution.
The Census Bureau will be releasing 2021 one-year estimates in the fall of 2022 which will be a standard release (here is the full 2021 data release schedule). The 2021 one-year estimates will be comparable to other standard releases. Data-Z will resume reporting one-year estimates when they become available.
According to the Census Bureau, It is important to remember that all ACS data are estimates. They “collect data from a sample of the population in the United States and Puerto Rico rather than from the whole population. To help you interpret the reliability of the estimates, the Census Bureau publishes a margin of error (MOE) for every ACS estimate.”