 Complete the following phrase:  Timo Glock was initially signed to compete for Marussia until the end of the 2014 season, but later announced that he would be leaving the team. Marussia team principal John Booth cited tough economic conditions as the reason for the team being forced to let Glock go, whilst Glock referenced the loss of tenth place in the 2012 World Constructors Championship to Caterham at the 