Pic related shows the risk of countries due to chink travelers. This table doesn't show people who traveled to china which means the # of cases is alot higher

>https://www.worldpop.org/resources/docs/china/WorldPop-coronavirus-spread-risk-analysis-v1-25Jan.pdf

I'm using south korea's # of cases of cases to extrapolate the number of cases in other countries and I'm also assuming that the r0 is the same throughout all countries.

To calculate the number of cases for other countries is simple:
([#] traveled to [country]) / (936.6k traveled to south korea) = (x cases in [country]) / (204 cases in south korea)

I believe the # of cases is severely under reported not just in china