For instance, from 1880 through the end of the 20th century, only one X-name managed to place among the top 1,000 U.S. baby names: Xavier. (It popped up once randomly in 1890, then came back to stay in 1948.) A second X-name wasn't able to crack the list for decades.
Finally, in 1996, Xena showed up to keep Xavier company. (It had become popular thanks to the Xena: Warrior Princess television series.) After that, other X-names appeared: Xander in 1999, Xzavier in 2000, Ximena in 2001, and Xiomara in 2004.
Even more impressive than how quickly they entered the charts was how swiftly these names have been climbing. As of 2008, Xander ranked #267 for boys and Ximena ranked #332 for girls. Xavier entered the top 100 in 2001 and now ranks 71st.
And it's not just names that start with X being affected by the trend. Names that simply include the letter X are also on the up-and-up. I skimmed the top 1,000 baby names for each of the following years to see how many names per year contained an X, and this is what I found:
1880 - 13 names
1890 - 16 names
1900 - 14 names
1910 - 16 names
1920 - 13 names
1930 - 12 names
1940 - 15 names
1950 - 18 names
1960 - 17 names
1970 - 18 names
1980 - 15 names
1990 - 25 names
2000 - 35 names
The number of names with an X remained relatively stable until 1990, when many new names made their debut. These included both variants of established names (such as Alexia and Alexandre) and names that were just completely new to the list (like Maximilian and Braxton).
Then in 2000, there was another jump. This second batch of debuting names also included both variants (such as Alexys and Alexzander) and total newbies (like Phoenix, Paxton, Jaxon and Maximus).
The stats for 2010 aren't here yet (of course), but it's worthwhile to note that the 2008 list features the largest number of X-containing names yet: a total of 38.
So what's the X-factor here? What's fueling all this excitement over the X? Expectant parents see the inclusion of exotic letters as a simple, easy way to make a baby name stand out. The X may be particularly attractive to these parents because, of all the unusual letters, X is the rarest and therefore the most distinct.
And...it can't hurt that Angelina Jolie has used an X in the names of three of her six children. :)