Does Uganda have more mobile phones than light bulbs?
It's sometimes said that there are more mobile phones than light bulbs in Uganda - where did this idea come from, and is it true?
In 2009, journalist Dara Kerr wrote about Uganda as "a place where cell phones could outnumber light bulbs". This appears to be the first time such a comparison was made.
It's worth noting, however, that in her article for CNet technology magazine, Kerr only said that this could be the case. Over time, as people have repeated the idea, the word "could" seems to have been lost. Now it's often stated as fact - even by Vodafone.
"The first time I heard about this was at the e-learning conference in Kampala in 2014," says Ugandan lawyer, Gerald Abila. "This intrigued me." So he decided to find out if it was true and started gathering statistics.
According to the Uganda Communications Commission there are 22.6 million mobile phone numbers registered in the country.
But that doesn't mean there are 22.6 million phones - it just reflects the number of Sim cards, says Calum Dewar of GSMA Intelligence, a research group that provides mobile phone data.
The number of Sim cards is "not a very good measure of mobile usage or ownership," he says. It is "above 100% of the population in many countries and it's actually above 200% in some".
In Uganda's case, people who own a mobile phone have, on average, 1.5 Sim cards, he says. They are swapped in and out of phones to take advantage of deals on different networks.
With that in mind, Dewar thinks the number of mobiles in Uganda is likely to be closer to 16 million.
Find out more
- More or Less is broadcast on BBC Radio 4 and the World Service
- Download the More or Less podcast
- More stories from More or Less
Next, Abila looked at light bulbs. The Uganda National Household Survey 2012/2013 reveals that the country has 7.2 million households, of which 14% use electricity for lighting - so approximately one million homes have electric lights.
There's no data on how many bulbs each one might have though, so Abila had to guess.
He assumed there was one light bulb in use for each person in these households. According to government data the average home has 4.7 people, so for ease Abila rounded this up to five. That gave him a total of five million bulbs.
So using these figures it looks as though there are three times more mobiles than bulbs in people's homes.
In comparison, in 2011 there were about 600 million light bulbs in British homes and at the end of 2014, there were 89.9 million UK mobile subscriptions.
Abila admits his calculations for Uganda are rough and his figures don't include bulbs in offices, airports, stations, cars, shops, universities, restaurants, or other businesses.
But even if his estimate for bulbs is doubled from five million to 10 million to try to allow for this, the number of mobiles still seems to be greater.
With so few concrete figures though, it's probably safest to stick to Dara Kerr's original comment - Uganda is a place which could have more mobiles than light bulbs.
Subscribe to the BBC News Magazine's email newsletter to get articles sent to your inbox.