We can, however, get a rough approximation of NRA membership by looking at how much money the group brings in each year via member dues. That information is made public through the group's IRS filings, which have been compiled by ProPublica and Mother Jones. Those numbers show a lot of annual variation, with no clear trend in recent years — a sign, perhaps, that membership is flattening out.
The NRA sells single-year renewable memberships for $40, with multiyear and even lifetime membership options available. It also periodically offers discounts for renewals or new memberships. That variation in price makes it impossible to reverse-engineer exact membership numbers from total membership revenue: For instance, $1,500 in membership revenue could come from 38 annual membership renewals or from one new lifetime membership.
Still, the group's total annual revenue from dues is a useful, if rough, barometer of the number of individuals who find the NRA's cause compelling enough to join the group. And that number has fluctuated considerably in recent years.
Since 2004, the group has averaged about $128 million a year in total membership revenue. But that number has varied from $72 million in 2006 to $228 million in 2007, a peak it hasn't come close to matching since.
Membership revenue seems to spike following mass shootings and the resultant national discussions about gun control and gun rights. For instance, that 2007 peak came in the year that a gunman murdered 32 people on the campus of Virginia Tech. And in 2013, membership revenue increased by 63 percent over the previous year, following the killings of 20 children and six adults at Sandy Hook Elementary School in late 2012.
Membership revenue declined slightly in 2016, the most recent year for which IRS data is available. The group also raised the price of annual memberships that year, which may have something to do with the decline.
But the NRA also takes in revenue from many other sources, such as donations. In 2016, for instance, a single donor gave nearly $20 million to the group, according to its IRS filing. Earlier this year, McClatchy reported that the NRA is under FBI investigation into whether a Russian banker funneled money through the group to help then-candidate Donald Trump.
That money from donations and other sources shows a much clearer trend than the membership revenue: It's been rising steadily. If membership is indeed flattening out, the NRA appears to be making up for it by taking in money from elsewhere. (The group did not respond to a request for comment from The Washington Post.)
One final point in support of the notion that membership numbers are flat: The NRA has been publicizing the same membership figure for nearly five years now. Several months after the Sandy Hook mass shooting, for instance, LaPierre boasted that membership had surpassed 5 million individuals. “By the time we're finished,” he told members at the group's annual meeting in 2013, “the NRA must and will be 10 million strong.”
But as of February, the group's “About the NRA” page states it has “nearly” 5 million members. The road to "10 million strong” is evidently turning out to be a long one.