The following is a map of Ukraine showing the number (in percentages) of searches made on Yandex in the Ukrainian language across Ukraine in Autumn 2010...
It reminds me a bit of this graph from a survey conducted by Gallup in 2008 which I have posted about here. I repost the chart below:
Unlike most surveys which ask people which language they consider to be their native, the above charts measure the actual language use in the population. An interesting method indeed, these charts show that the vast majority of people in Ukraine give preference to Russian.
For those who know Russian, I suggest you read this.