I don't have statistics but it seems like around 90% of Russian girls you meet have one of 6 names:
Tatiana (aka Tanya)
Olga
Natalia (aka Natasha)
Elena (pronounced Ye-lay-na, aka Lena)
Ekaterina (ye-kat-er-ee-na, aka Katya)
Irina (eer-ree-na, aka Ira)
Common but somewhat less so are Yulia, Anna, Maria (Masha), Daria (Dasha), Alexandra (Sasha), Evgenia (Zhenya), Lyubov (Lyuba) or Lyudmilla (Lyuda, Milla), Larissa, Vera, Valeria (Lera), Valentina (Valya), Antonina (Tonya), Sofia (Sonya) and Ksenia
A quick scan of the female employee list (which I have because of having to organize the festivities last Friday) shows 6 Tatianas out of 76 women
