I'm searching the percentage of each attachment style in the general population (adult) in order to make some comparisons with the participants of my study.
In studies recognizing three attachment classifications (secure, avoidant-insecure, and resistant-insecure), about 20% of American infants have been classified as avoidant insecure, 70% as secure, and 10% as resistant-insecure (Ainsworth et al 1978).
Van IJzendoorn and Kronenberg's 1988 meta-analysis supports these earlier findings. Studies of disorganized attachment depend on the particular sample studied. The prevalence of disorganized attachment among middle class, white American children is between 12-15% in the Mary Main studies (Main and Solomon 1990). Infants of adolescent mothers have a rate around 30% (Broussard 1995). And infants of abused mothers and psychiatrically ill or substance abusing mothers can be as high as 70-80%! (Carlson et al., 1989). See the Grossmann's work for information on cultural and regional differences in prevalence of organized attachment types such as avoidant.