What elbowin said, it was an error with New York's name counting that year.
If you look at the chart for 1989, you'll also see
Alexande [Alexander]Alexandr [Alexandra]Stephani [Stephanie]Christin [Christine/Christina-- this spelling was used as a name too but had a sharp increase in 1989 and dropped the next year because of the error]Elizabet [Elizabeth] Katherin [Katherine]
Or you can just look at this https://www.behindthename.com/name/alexande/top?compare=alexandr+stephani+elizabet+katherin
This message was edited by the author on September 19, 2020 at 12:44 PM