Based on the number of current legislators, calculate the percentage of legislators that served in 21st-Century.
percentage = MULTIPLY(DIVIDE(SUM(strftime('%Y', start) between '2000' and '2017'), COUNT(bioguide_id)), 100.0); 1st-Century refers to strftime('%Y', T2.start) between '2000' and '2017';
SELECT CAST(SUM(CASE WHEN strftime('%Y', T2.start) BETWEEN '2000' AND '2017' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T1.bioguide_id) FROM current AS T1 INNER JOIN `current-terms` AS T2 ON T1.bioguide_id = T2.bioguide