Historical exchange rates are only available on paid fixer.io accounts.
fixer_historical(date = NULL, base = "EUR", symbols = NULL)A date in YYYY-MM-DD format, or any value that can be coerced
to YYYY-MM-DD format with as.Date(). Defaults to NULL, which
returns the latest conversion data.
The base currency to index other currencies against.
Defaults to "EUR". Can only be changed with paid plans.
The symbols of currencies to return exchange rates for.
Defaults to NULL and returns all available currencies. See
fixer_symbols] for details on symbol options.
A tibble with exchange rates to the base currency on a given date.
if (FALSE) {
historical <- fixer_historical(date = "2017-05-18")
}