This 2015 article mentions that millions of files now include utilities so I would imagine since then this accounts for more files. http://www.experian.co.uk/blogs/consumer-advice/household-bills-better-credit/. What is important to point out is that The Rental Exchange was established to help those in social housing with 1.5m records now reporting. This is being brought to the private rented sector next due to the benefits I’ve mentioned previously.
From the November 24th second reading of the Creditworthiness Assessment Bill in the House of Lords, I would like to quote the founder of The Big Issue and Crossbencher John Bird,
If you look at the work that I have been doing over the last 26 years, it has nearly always been aimed at how we can dismantle poverty in the lives of the neediest. One escape route is obviously around education and housing and the opportunities that you get through work—but another thing, which is hidden, is how expensive it is to be poor. It is incredibly expensive. If you are poor, you pay more for your electricity, gas and credit.