  People mobility data sets played a role during the COVID-19 pandemic in
assessing the impact of lockdown measures and correlating mobility with
pandemic trends. Two global data sets were Apple's Mobility Trends Reports and
Google's Community Mobility Reports. The former is no longer available, while
the latter will be discontinued in October 2022. Thus, new products will be
required. To establish a lower bound on data set penetration guaranteeing high
adherence between new products and the Big Tech products, an independent
mobility data set based on 3.8 million smartphone trajectories is analysed to
compare its information content with that of the Google data set. This lower
bound is determined to be between 10^-4 and 10^-3 (1 trajectory every 10,000
and 1000 people, respectively) suggesting that relatively small data sets are
suitable for replacing Big Tech reports.
