Twitter now has 10 million active users in the UK, out of 140 million worldwide, the company has revealed – and 80%, an unusually high number, access it through mobile phones.
The data about the UK, revealed for the first time by the company, indicates that 8 million who logged in to the company's site in the past 30 days did so from a mobile phone, compared to Twitter's global average of 55%.
Unfortunately this does not account for faked/bot created accounts.
AFAIK there is no means to weed out faked from man-made accounts. Although one of the bots characteristic is their capability to answer a tweet in a millisecond. This combined with a few more bot "fingerprints" such as profile similitude and other suspicious feaures should allow to create a decent bot killer tool.