The increases are seen partly as a result of the simplification of procedures for joining the society and for upgrading membership, including online Web facilities.
Membership moved just above 37,000 last January but fell to 36,260 in February before another surge to almost 37,190 in March. After further slight dips there was another rise above 37,000 in June and by October there was the highest-ever total - 37,299.
Marketing director Alida Macchietto said, "Applications have been above target, and it has become evident that the results are directly connected to recent changes."
More information about membership grades is now provided from the society's Web site. People can join the society and pay their fees via the Web.
Procedures for moving to a professional grade are being streamlined, with a shorter application form and the elimination of assessment interviews if a candidate is clearly eligible for a particular grade.
Meanwhile, the subscriptions for the three main non-professional grades of affiliate, student and graduate - the professional members of the future - are being brought into line. There has been 13% growth in the number of student and graduate members in the last year and a 6% increase in the number of affiliates.
More steps to encourage membership will be made this year. The BCS governing council recently approved a new points system to further simplify and speed up the path to professional membership grades. And an extra grade is planned for people who work in IT but who do not yet qualify for professional membership and are therefore currently put in the affiliate grade.
These moves could take membership levels even higher. "If the growth is indeed directly linked to these changes, it is reasonable to expect this upward trend to continue," said Macchietto.