Time when Naira had more value than dollars

Recently we got this from a friend about  her mum's International passport that showed that Naira was worth more than dollars in 1981. Read what she sent below:

"I'm an ardent reader of your blog and thought I share this with everyone. Stumbled on my mum's old int'l passport and apparently Nigeria was once a great country. Once upon a time N1000 = $1480 back in 1981"