An important piece of data to the question of when we will welcome our new robot overlords is just how many robots are there in the world right now? (Answer: about 1,000,000 - still a puny number compared to humans, so Google may want to wait a while before it achieves sentience).
Focus Magazine has a nifty infographic about robots, specifically robots in the workplace. One interesting (and I'm sure controversial) nugget of info is that if you think illegal immigrants are taking your jobs, then you're blaming the wrong party:
It is estimated that by the year 2025, robots will have taken over nearly one-half of all jobs in the United States. In certain job sectors, robots may even completely replace human workers.
Link - Thanks Jason!