Something seems to have happened in NL in March that generated some demand for it, but it seems to have vanished now:
https://trends.google.com/trends/explore?geo=NL&q=%2Fm%2F012...
Your link shows a peak at the time you mention but the interest in subsequent months has been around 4 times higher than it was prior to the inauguration, so it seems inaccurate or even misleading to say that demand has "vanished."
That "something" is just people searching for this news story, rather than interest in signal for the sake of using it.
https://en.wikipedia.org/wiki/United_States_government_group...
NL clearly has some background interest in signal however, unlike the UK, which spikes on this story alone:
https://trends.google.com/trends/explore?geo=GB&q=%2Fm%2F012...