For hundreds of years, human society has relied on money in both business and personal life.Now, with a mobile banking system called M-Pesa, people can use credit on their phones to pay for things in shops, pay their bills and their children's school fees, and receive their salary.Kenya has led a revolution in mobile banking, and other developing countries have followed its example.Statistics show that since the decrease in the cash economy, there isn't as much crime in Sweden: the number of bank robberies dropped from 110 in 2008 to only 16 in 2011.Instead, all the passengers have to pay for their tickets by card or mobile phone before they get on. Some businesses only take cards, and there are banks which don't deal with any notes or coins.Many countries in the developing world have found that mobile phones are perfect for transferring money.In 1601, Sweden became the first European country to use banknotes.In most Swedish cities, buses don't take any cash.It's not just richer countries that are becoming cashless.On the other hand, lots of Kenyans (over 95%) have mobile phones and carry them all the time.This, however, may soon come to an end, as technology continues to change the way we live our lives.Now it could be one of the first countries to stop using cash.In a cashless society, you don't need to worry about having enough change for the bus.That's great if you don't like carrying too many coins in your pocket.However, not all Swedes like the idea.Elderly people, who may need some help with the technology, say their lives are now harder.Small businesses are also unhappy because they have to pay a little money to the bank each time somebody pays them using a card.For example, in Kenya, only a few people (under 20%) have a bank account.A society without cash is also safer.