The 21 currently declared Democrats running for the 2020 Democratic presidential nomination are competing in one of the largest, most competitive, and most unpredictable fields in modern history.

To determine what proportion of likely Democratic voters are aware of each candidate, INSIDER has been conducting a recurring SurveyMonkey Audience national poll.

Here are all the best and least-known 2020 Democratic candidates as of May 2, according to INSIDER polling.

Visit Business Insider's homepage for more stories.

The 21 currently-declared Democrats running for the 2020 Democratic presidential nomination are competing in one of the largest, most competitive, and most unpredictable fields in modern history.

For the many lesser-known candidates in the field, the most important thing they'll need to make it to the first caucuses and primaries next February is to introduce themselves to as many Democratic voters as possible, raise their name recognition, and create a lasting impression among the voters they're trying to court.

To determine what proportion of likely Democratic voters have heard of each candidate, INSIDER has been conducting a recurring SurveyMonkey Audience national poll. You can download every single poll here, down to the individual respondent data.

Read more about how the INSIDER 2020 Democratic primary tracker works.

At this point in the race, we're mainly interested in using our polling to figure out:

What percentage of Democratic voters are familiar with each candidate in the first place.

How Democrats rate each candidate's chances of beating President Donald Trump in a general election match-up.

If a given candidate were to drop out of the race, who their supporters would flock to next.

This ranking of the best and least-known 2020 candidates comes from the most recent version of our SurveyMonkey poll which ran the week of May 6 and surveyed 3,320 Democratic voters.