_id	Year	Data Source	Count
9	2019	Network Manager (EUROCONTROL)	18970
10		OpenSky Network (ADS-B)	15904
11	2020	Network Manager (EUROCONTROL)	14654
12		OpenSky Network (ADS-B)	13478
13	2021	Network Manager (EUROCONTROL)	17690
14		OpenSky Network (ADS-B)	16348
15	2022	Network Manager (EUROCONTROL)	19063
16		OpenSky Network (ADS-B)	18061