The figures below are derived from analysis of data generously provided by Domain Tools.

NOTE: This dataset does not cover the entire Internet, therefore none of the graphs below represents Internet-wide figures. They may differ greatly from studies conducted using other datasets. However the trends within this set, the changes over time, are believed to be representative of Internet-wide trends and therefore provide valuable insight.

Adoption

This section shows the number of published DMARC policies, as of when they were first observed in DNS, provided that they still have a DMARC policy published when this dataset was most recently evaluated. In other words a domain that first published a DMARC policy in January 2016 will be included in the total for January 2016, provided that the domain still had a valid DMARC policy published in January 2021 (for a dataset that covers through the end of 2020, in this example).
DMARC growth 2015 through 2021

The graph above only shows the data from 2015 through the end of 2021, but a similar graph starting in 2012 is available here. In November 2018 there was a surge of 5MM new DMARC records published, most of them at unusual labels like _dmarc.mx.mx.mx.example.com, believed to be from a single hosting organization. Most of those records may have been mistakes as they were no longer published by 2020, but even without them the number of published records increased by nearly 50% in that month.

This graph shows the total of valid DMARC policies every six months from the end of 2016 through 2021.

Total valid DMARC policies every six months since 2016

The following graph covers the same set of domains, but shows the number of valid DMARC records published for the first time in each month. The chart starts in January 2017 because the large scale needed for later months would make the earlier monthly totals invisible.

DMARC growth 2015 through 2021

There is clearly a large increase in new records in June 2021, four times the average number of new records in the preceding 12 months. Referring to the first graph this is only a 13% increase in the total number of active DMARC records at the time, but the surge continued for the following two months. While the number of new records was lower in the fourth quarter, it was still much higher than the first half of the year.

Policies

These graphs try to show the relative proportion of each DMARC policy option among all the active, valid DMARC records in the dataset. First is the overall policy mix at the end of CY2021.

CHART DMARC policy mix at end of 2021

Below is a chart of the policy mix as captured at the end of each year since 2016.

CHART DMARC policy mix year-over-year

The trendlines on this chart show that, on average, the number of p=none policies have been gradually declining while the others have been gradually increasing.