https://wccftech.com/ios-13s-location-privacy-controls-have-reduced-data-collection-by-advertisers/

iOS 13’s revamped location privacy controls have had a major impact on background data collection by advertisers and marketers. Android 10 also has similar location privacy control improvements, however, its market share is too low to make a difference yet.

Background data collection has dropped by 68% as per a report by Location Sciences, a company that specializes in location data verification for advertisers. Foreground data sharing has also reduced by 24%. Another report by Digiday says that user opt-in rate for allowing background location data access has fallen below 50%.