Transparency International Czech Republic and Bisnode published an analysis of flows of money into tax havens via entities that won public contracts or tapped EU funds. Since 2007. it has been around CZK 244bn. According to the analysis, public contracts worth CZK 153bn were awarded to companies, whose owners reside in one of tax havens (primarily in the Netherlands, Cyprus or Luxembourg). Around 1% of the companies analyzed were connected with politically active persons. Read the study (in Czech).  

Also, in an article published by Radio Zet, Lenka Andrýsová of EY says the level of corruption in the Czech Republic is not that high - somewhere in the middle between the East and the West - with the banking and the public sectors being the most corrupt. Surveys (e.g. by OECD or Transparency International) often rely on estimates and personal opinion rather than hard data.