Enrollment in insurance plans through President Obama's health care law is trailing expectations -- and this cannot be explained away by the early technical problems that plagued the program's rollout.

The above chart looks at how the reported signups for health care plans through the program's insurance exchanges match up against the original projections by the Department of Health and Human Services.

What it shows is that in four out of five months since the exchanges launched Oct. 1, signups have trailed original enrollment projections, which were made in an HHS memo written weeks before the exchanges opened.

Though the trend was broken in January, when reported signups exceeded projections for the month by 86,171 individuals, things reversed in February. HHS reported Tuesday that the pace of signups slowed in February and they were 329,047 (or 26 percent) off of projections for the month.

The February drop-off cannot be explained by the fewer days in the month, as HHS officials were presumably aware that there were only 28 days in the month when they made their projections.

Cumulatively, HHS has reported that 4.2 million have signed up for a plan, which compares to the 5.7 million originally projected. Original projections saw 7 million enrollments by March 31, the end of the open enrollment period.

HHS numbers count those who have selected a plan as having enrolled, regardless of whether they have been consistently paying premiums -- the traditional way of measuring enrollment. HHS still hasn't released data that takes into account those who have paid, but insurance industry sources have estimated that the number of non-payers is in the 20 percent to 25 percent range.