Facts:   - weight: 165 lb kg on    - height: 6 ft 1 in m on      - strokes: freestyle    - fullname: david charles johnson    - birth date: 20 february 1947    - name: david johnson    - club: philadelphia aquatic club    - birth place: wilmington , delaware    - collegeteam: yale university   Based on these bullet points, write a short biography describing the life of david johnson -lrb- swimmer -rrb- .
Answer:
david charles johnson -lrb- born february 20 , 1947 -rrb- is an american former competition swimmer .johnson represented the united states at the 1968 summer olympics in mexico city .he swam for the gold medal-winning u.s. relay teams in the preliminary heats of the men 's 4x100-meter freestyle and men 's 4x200-meter freestyle .he did not receive a medal in either event because only relay swimmers who competed in the event final were eligible for medals under the 1968 olympic rules .johnson attended yale university , where he swam for coach phil moriarty 's yale bulldogs swimming and diving team in national collegiate athletic association -lrb- ncaa -rrb- and ivy league competition from 1967 to 1969 .he was a member of the yale team that won the ncaa national championship in the 800-yard freestyle relay in 1968 .he graduated from yale college in 1969 , and the yale school of medicine in 1973 .