The median income in this zip code has shown an overall upward trend. It increased from $59,889 in 2013 to $70,724 in 2022, representing an 18% increase over the decade. A notable jump in median income occurred between 2018 ($60,629) and 2019 ($70,877), suggesting a significant economic shift during this period.

The population has fluctuated over the years. It increased from 467 in 2013 to a peak of 505 in 2014. It then declined to 381 in 2021 before rising again to 460 in 2022.

The stability of the racial composition in this area is unusual compared to many other parts of the country, which have seen increases in diversity, particularly in urban and suburban areas. This could be due to factors such as limited economic opportunities for diverse populations, lack of immigration to the area, or possible cultural or social factors that make the area less attractive to non-white populations.

This level of racial homogeneity and its persistence over time is increasingly uncommon in many parts of the United States, especially in areas with rising incomes, which often correlate with increased diversity.

In conclusion, zip code 50120 in Haverhill, Iowa, has seen economic growth over the past decade while maintaining its status as a low-diversity, white-majority area, contrary to national trends towards increased racial diversity. This demographic stability amid economic growth could be a subject for further investigation into local social, economic, and policy factors that might be influencing these trends.