It was confirmed in an investigative report by website Famitsu that Nintendo has sold around 5,007,367 Nintendo Switch units in Japan alone. This record was achieved in just 79 weeks (1.5 years) since this highly-demand console went on sale.
As of June 30, the Nintendo Switch has so far sold around 19.67 units worldwide. Their report has also revealed the top selling games of the console in Japan:
1. Splatoon 2 (2,621,928 copies)
2. Super Mario Odyssey (1,788,228 copies)
3. Mario Kart 8 Deluxe (1,738,502 copies)
4. The Legend of Zelda: Breath of the Wild (1,065,780 copies)
5. Kirby Star Allies (591,721 copies)
Nintendo expects that they will sell 20 million units of its console by the end of the fiscal year on March 31, 2019.
Source: Mantan Web, Famitsu