Percent means one hundred.  If someone gives one-hundred percent of his income to a charity it means that he gives his total income.  One-hundred percent is the zenith.  One cannot give more than that in treasure, effort, or anything else that can be measured over a fixed period of time, most often a year.

Of course, we can use percentages above a hundred when comparing measurements from different periods of time.  For example, we can say that the population of the United States has increased around 400% since the beginning of the twentieth century (4 times larger).

In the world of sports and politics, the word percent is often used somewhat loosely.  An athlete will often boast of his or a teammate having made a 110% effort.  That statement is impressive, but in terms of actual measurement it means nothing.

Insofar as politics, I have a clear memory of an incident during the 1972 Presidential campaign between Richard Nixon and George McGovern.  Senator Thomas Eagleton had been chosen to be McGovern’s running mate, but early in the campaign it was disclosed that Eagleton had received electroconvulsive therapy during an episode of severe depression.  There were calls for Eagleton’s replacement, but McGovern announced that he stood behind the senator a thousand percent.

Shortly thereafter Eagleton was replaced as Vice-Presidential candidate by Sargent Shriver.

We are not quite certain what McGovern meant by “a thousand percent,” but it is obvious that he meant something less than one-hundred.