If you think you can do it (i.e. build a successful company), you probably can do it regardless of your status (in school, unemployed or while working for another company). Actually there are numerous examples of people who have done it and each one has their own story. You really can't generalize or conjecture statistics for the future so 1% stat including margin of error is moot. I would rather rephrase your statement as "An entrepreneur is more likely to be passionate about his/her ideas and opening his/her company than building a successful career in another company".