>10^8, often in the range of 10^9-10^10 cells
||Michael Lynch and Georgi K. Marinov, The bioenergetic costs of a gene, PNAS 2015 doi: 10.1073/pnas.1514974112 link p.3 left column 2nd paragraph
|| Lynch M (2007b) The Origins of Genome Architecture (Sinauer, Sunderland, MA).  Lynch M, Bobay LM, Catania F, Gout JF, Rho M (2011) The repatterning of eukaryotic genomes by random genetic drift. Annu Rev Genomics Hum Genet 12: 347 – 366. doi: 10.1146/annurev-genom-082410-101412.PubMed ID21756106
||P.3 left column 2nd paragraph:"Using this approximation, a bacterial cell with a representative volume of 1μm^3 will have a replication-associated cost of DNA≈(4×10^−9)Lg, so the fractional drain on the total cellular energy budget can be as high as (4×10^−8) for a small 10-bp insertion and (4×10^−6) for a gene-sized insertion of 1,000 bp. To put this into perspective, free-living bacteria typically have effective population sizes >10^8, often in the range of 10^9 to 10^10 (primary sources). Thus, when growing at maximum rates, bacteria experience efficient enough selection to remove insertions as small as 10 bp (and even smaller when Ne>10^8)."