Dear Leonard,

I fear there is no perfect answer to this, but I would recommend to consider one of the following options:

a) take a large sample of tweets and look for geo tagging information to get a rough estimate (although geo / location information is rarely used explicitly om Twitter).

b) do text analysis on the tweet content in order to determine whether its from Zibabwe or not

c) run ad hoc visual analytics using tweetping.net over a time slice of at least some hours - this might give you at least a rough idea of how many people are active on Twitter in Zimbabwe.

d) more elusive alternatives might include starting a crowdsourcing survey ...

Kind regards

Christian

Thank you so much Christian. The answers are innovative and it is exciting to try them

What I have forgotten in my answer above:

You might scan the various social media analytics websites for country-specific Twitter data.

For example, at http://www.beevolve.com/twitter-statistics/ you will find world map of Twitter activity showing rather low values for Zimbabwe.

Kind regards

Christian

Leonard, I know that this not an answer to your question but I thought it might be also interesting. Here you will find the most popular Twitter profiles from Zimbabwe http://www.socialbakers.com/statistics/twitter/profiles/zimbabwe/

Thank you very much Dominik. I can see that knowing the popular Twitter profile also gives important insights on who tweets in Zim. Thank you very much