Table 6. Temporal trends of the top 20 mobile technologies.

Mobile tools	2017	2018	2019	2020	2021	Trend
Flutter	0.09	1.05	3.19	5.59	7.23	7.53 ⇑
Dart	0.05	0.57	1.57	2.51	3.17	3.36 ⇑
Kotlin	0.60	1.45	2.25	2.65	3.09	3.25 ⇑
React-native	1.55	2.56	3.39	3.65	3.97	3.01 ⇑
Reactjs	0.43	0.77	0.88	1.30	1.33	1.01 ⇑
Android-studio	1.04	1.53	1.25	1.81	1.98	0.61 ⇑
Javascript	0.96	1.07	1.19	1.36	1.41	0.52 ⇑
Firebase	1.37	1.73	1.56	1.80	1.76	0.37 ⇑
Android-recyclerview	0.51	0.65	0.65	0.57	0.49	−0.06 ⇓
Xcode	1.43	1.33	1.33	1.49	1.23	−0.25 ⇓
Json	0.65	0.57	0.51	0.48	0.43	−0.25 ⇓
C#	0.71	0.65	0.65	0.53	0.42	−0.26 ⇓
Firebase-realtime-database	0.67	0.67	0.52	0.44	0.39	−0.29 ⇓
Ionic-framework	0.96	1.00	0.92	0.66	0.60	−0.30 ⇓
Xamarin	1.04	0.99	0.89	0.78	0.57	−0.40 ⇓
Java	3.67	3.78	3.79	3.27	2.83	−0.91 ⇓
Objective-c	1.48	0.82	0.54	0.45	0.32	−1.49 ⇓
Swift	5.53	5.78	5.67	5.15	4.16	−1.77 ⇓
iOS	7.54	6.35	5.36	4.64	3.95	−3.85 ⇓
Android	15.53	15.23	13.96	11.53	10.99	−4.81 ⇓