The country’s largest union has been slowly losing members since the start five years ago of its campaign to raise the minimum wage to $15 an hour.

An analysis of the 2016 financial disclosures from the Service Employees International Union (SEIU) to the Department of Labor by the Center for Union Facts (CUF) reveals that the union spent over $90 million on the Fight for $15 minimum wage campaign since 2012 without a single major policy victory.

The watchdog CUF says that in addition, membership for the union -- which represents public service workers, nurses, hospital staff and home-care providers, building services, security guards and food service workers -- has been waning since the start of the initiative.

“After five years and $90 million or more spent on the Fight for $15 campaign, the [SEIU] has failed to make progress on the metric that matters most: Getting more dues-paying members in the restaurant industry," CUF Executive Director Richard Berman said to Fox News. "It was reported earlier this year that the SEIU is cutting back its spending in the Trump era, and the costly and unproductive $15 campaign is surely on the chopping block.”

“An SEIU pullback on $15 wouldn't be surprising -- the UFCW [United Food and Commercial Workers] ended its commitment to the ‘OUR Walmart’ campaign after it became clear that employees had no interest in what they were selling. It's a lesson the SEIU may soon learn the hard way."

While the SEIU’s membership increased from 1,887,941 employees in 2015 to 1,901,161 employees last year, the union's membership has actually declined over the past six years. In 2011 when the union started the Fight for $15 it claimed 1,921,786 – 21,000  more employees than it had in 2016.

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A protestor speaks on a bullhorn as he and others protest near a McDonald's restaurant along the Las Vegas Strip, Tuesday, Nov. 29, 2016, in Las Vegas. The protest was part of the National Day of Action to Fight for $15. The campaign seeks higher hourly wages, including for workers at fast-food restaurants and airports. (AP Photo/John Locher)

“While the SEIU has scored some legislative victories, the union continues to bleed money with no major restaurant organizing win to show for it,” Berman said. “Even former SEIU boss Andy Stern has acknowledged that the $90 million Fight for $15 wage campaign isn't sustainable.”

At least $19 million was spent on the Fight for $15 campaign in 2016, according to the financial disclosures. The CUF believes that the number is a conservative estimate because it excludes items such as staff salaries, expenses paid for additional legal services and money paid to certain outside advocacy groups.

Over $14 million in campaign funds went to workers organizing committees, which are effectively satellite offices within the SEIU organization.

Officials for the SEIU did not immediately respond to requests for comment.

News of the union’s financials comes on the heels of a national protest organized by SEIU for next week.

The Fight for $15 organization is joining forces with a cluster of Black Lives Matter groups to launch their first national joint action on April 4, the 49th anniversary of King's assassination, with "Fight Racism, Raise Pay" protests in two dozen cities, including: Atlanta; Milwaukee; Memphis, Tennessee; Chicago; Boston; Denver; and Las Vegas.