Just to cut this rumor before it spreads, the article imem speaks of comes from sohu.com.
In that article, it is mentioned that the capacity of their largest factory, the Nokia Beijing factory is about 2M Lumias per month. They also mention that at some point, the devices made there were manufactured in the following ratio:
Lumia 920: 20k / day or 600k / month
Lumia 820: 25k / day
Lumia 620: 20k / day
This ratio has most likely long since been adjusted to suit the market demand more accurately, but at some point it was roughly this.
I would like to point out that it's useless to try to use these numbers in any sort of estimations or calculations because they are not official, up to date nor even complete. We have no idea when the device production began and these numbers only speak of the Beijing factory when Nokia manufactures smartphones also in other locations such as Mexico and South Korea.