Steven has been quite popular in the U.S. in decades past. From 1941–2007, it was in the Top 100, and was in the Top 20 from 1949–76. Its highest rank was #10, from 1955–61. By 2016, it had dropped down to #167.
The variant Stephen has followed a similar trajectory, though it’s been much more popular historically. However, it’s never been more popular than #19, from 1949–51. In 2016, it was #265.
I completely understand why Steven became more popular than Stephen, since it matches the pronunciation. For years, I believed Stephen was pronounced Stef-in, since we don’t pronounce Stephanie with a V sound. Since the first E is long, PH turns into a V sound instead of its usual F.
Outside of the Anglophone world, other forms of the name include:
1. Stepan is Russian and Armenian. Russian nicknames include Styopa, Stepa, Stenik, Stenchik, Stenka, Stepik, Steshok, Steshka, Stefka, Stepka, Stesha, Stenya, Styopka, Stepok, Stepunka, and Stepanik.
2. Stefano is Italian.
3. Stefan is German, Dutch, Scandinavian, Bulgarian, Macedonian, Polish, and Serbian. The variation Štefan is Slovak, Slovenian, and Croatian; Štěpán is Czech; Stefán is Icelandic; and Ștefan is Romanian. The Dutch nickname is Stef; Serbian and Croatian diminutives include Stevo, Stipe, and Stipo; the Polish base nickname is Stefek; and the Romanian nickname is Fane.
4. Stevan is Serbian and Croatian.
5. Stipan is Croatian.
6. Stjepan is Serbian and Croatian.
7. Steffen is Dutch, Norwegian, Danish, and Low German.
8. Stephan is German and Dutch.
9. Staffan is Swedish.
10. Steffan is Welsh.
11. Steafan is Scottish.
12. Steaphan is also Scottish. The nickname for both is Steenie.
13. Stefanus is the official Dutch form, used on legal documents and birth certificates.
14. Szczepan is Polish.
15. Stiofán is Irish.
16. István is Hungarian. Nicknames include Istók, Pista, Pisti, Isi, Istó, Pityu, Isti, Pistu, Pityus, Petya, and Pesta.
17. Stepane is Georgian.
18. Stefanos is Greek.
19. Stephanos is also Greek.
20. Estevão is Portuguese.
21. Étienne is French.
22. Stéphane is a French variation, most popular in the 1970s.
23. Estève is Occitan, and Esteve is Catalan.
24. Esteban is Spanish.
25. Estavan is a Spanish variation.
26. Estevo is Galician.
27. Stefans is Latvian.
28. Steponas is Lithuanian.
29. Tipene is Maori.
30. Tapani is Finnish.
31. Tahvo is also Finnish. The nickname for both is Teppo.
32. Eappen is Malayalam, a language spoken in India.
33. Istebe is Aragonese.
34. Kepano is Hawaiian.
35. Sćěpan is Sorbian.
36. Stiven is an alternate Georgian form.
37. Styve is Québécois.
38. Tēpene is an alternate Maori form.
39. Estepan is Basque.
40. Ixtebe is also Basque.