With a nearly 30 percent decline in its black-market value against the U.S. dollar, the Venezuelan currency continued to drop at a stunning rate in May, a development likely to put further pressure on the South American nation's fragile economy, Bloomberg reported.

The bolívar fuerte has seen similar downturns before: In informal trading, it fell 33 percent in November of last year, 20 percent in January 2014 and 26 percent in October 2013.

But unlike in the past, when people trusted that the currency was worth more than just the gold and cash reserves of Venezuela's Central Bank, its black-market rate is now about three times higher than the so-called "implicit rate" -- or the number of bolívars in circulation divided by such reserves, the business publication detailed.

That translates into an unofficial exchange rate of 423 bolívars per dollar, up from 279 at the beginning of May -- more than 67 times the lowest official rate, which is used for priority imports. Depending on the circumstances, the Venezuelan government authorizes foreign-currency purchases at 6.3, 12 and 199 bolívars per dollar, respectively.

In a largely futile attempt to curb the black market, the government of embattled President Nicolás Maduro, meanwhile, has attempted to shut down an application called "DolarToday," which provides Venezuelans with an approximation of the latest exchange rates, Business Insider noted.

Maduro has contended that the app is part of an "economic war" against his administration, but citizens have circumvented his ban by using Twitter and other websites that pick up DolarToday's content, the publication added.

Economist Luis Vicente León told the Venezuelan online daily Informe 21 that it was tricky to calculate the unofficial bolívar value, which is the result of a "dark, opaque market." Apps like DolarToday primarily monitor transactions that take place in the border areas with Colombia, he added.

"The exchange rate, empirically, is the average of the exchange rates that could be seen on a given day," the economist explained. "The dollar is worth what the people are willing to pay for it; that's its value," Vicente León added.