This is from the US Center for Disease Control:

Antibody Response to Vaccination
Licensed formulations for both vaccines produce high (>95%) rates of protective antibody (anti-HBs >10 mIU/mL) when the complete series is administered in different schedules to infants, juveniles, and adults aged <40 years (5). Among healthy adults, 30%--50% develop a protective antibody response after the first vaccine dose, 75% after the second dose, and >95% after the third dose (5--9). Increasing the interval between the first and second dose of vaccine has little effect on immunogenicity or final antibody titer, although data are limited regarding intervals >2 months among adults (5,8). The third dose confers the maximum rate of seroprotection; it primarily acts as a booster and confers optimal long-term protection through the induction of maximum immune memory (5,9). Both licensed vaccines administered on a 0-, 1-, and 6-month schedule produce a >95% final seroprotection rate among adolescents and healthy young adults, and studies indicate that vaccination of adolescents and adults on a 0-, 2-, and 4-month, and adolescents on a 0-,12-, and 24-month schedule, achieved final seroprotection rates similar to the 0-, 1-, and 6-month schedule (8--10). In addition, a 2-dose vaccination series using Recombivax HB? at the adult dosage has been demonstrated among adolescents aged 11--15 years to produce protective antibody responses equivalent to that of the 3-dose series, although the long-term protection afforded from this schedule is not known (8,11).
The duration of vaccine-induced antibody and protection from hepatitis B virus (HBV) infection has been evaluated among vaccinated infants, juveniles, and adults (5,12--14). Studies indicate that although loss of detectable anti-HBs has ranged from 13% to 60% by 9--15 years after vaccination, immune memory provides protection from HBV infection, and protection remains intact for >15 years, the longest period for which follow-up data are available (5,12--14). Because of the long duration of protection afforded by the 3-dose vaccine series, booster doses of vaccine are not needed among vaccinated immunocompetent juveniles or adults.
So, in the US, they only track for 15 years, but believe that there is sufficient immunity left at the 15 year mark not to recommend a booster.