Annual indices provide a summary of year to year changes in populations. Here, we present indices summarized at the survey-wide level, but lower-scale indices (for states, provinces and other regions) are also available from the BBS Office. Indices are estimated from the residuals left after the regional trend and observer differences are eliminated from the data. We do not use simple regional means of counts for a year as indices because the regional means are affected by a variety of factors that introduce spurious patterns of change over time.