Nearly two decades into the 21st century, Nielsen is ready to ditch dead trees for digital.

The measurement company announced Wednesday that it will introduce electronic measurement in 140 television markets that still rely on the old-school method of gathering paper diaries from viewers to calculate television ratings. Nielsen expects to have electronic measurement for local television ratings in place in all markets by mid-2017. The last of the paper diaries are slated to disappear by early 2018.

Among the forms of measurement being introduced in those markets still reliant on pen and ink is Nielsen’s Return Path Data, which measures information directly from set-top boxes.

“By tapping into the strengths of Return Path Data and electronic measurement, and combining it with Nielsen’s gold-standard panels and meters, we will be delivering a superior product to help all local clients address current challenges and be better positioned for future trends,” said Megan Clarken, president, Nielsen product leadership. “These enhancements are part of Nielsen’s commitment to invest in and transform how local TV is measured in a cross-platform world across all screens and devices.”

Nielsen covers 210 designated market areas. The 140 television markets currently using paper diaries are smaller ones such as Panama City, Fla.; Springfield, Mo.; and Bakersfield, Calif. The top 25 markets, and others, are all measured electronically.

The paper-diary system is a holdover from the earliest days of Nielsen’s efforts to measure television viewing — one that the company still relies on heavily, even as electronic measurement and the company’s People Meter devices have moved to the core of its business. Nielsen still collects 2 million paper diaries every year during the sweeps in February, May, July and November. The diary system relies on audience members keeping honest and accurate records of their television viewing habits.

The new electronic effort will make it possible for Nielsen to provide measurement in all 210 designated market areas on a daily basis.