According to Statista, the share of mobile retail e-commerce as a percentage of global retail e-commerce sales is set to rise to 72.9% by 2021.
In the graph below, you can see that the mobile retail e-commerce sales accounted for 52.4% in 2016 and rose to 58.9% in 2017.
The rest of the figures were forecast to be 63.5% in 2018, 67.2% in 2019, and reaching 70.4% in 2020.

References:
- Clement, J. (2019). Mobile retail commerce sales as percentage of retail e-commerce sales worldwide from 2016 to 2021 [Online]. Statista.com. Available at: https://www.statista.com/statistics/806336/mobile-retail-commerce-share-worldwide/ (Accessed: 22 Oct 2020)