is used at every act of intercourse. Actual failure rates are higher than perfect-use rates for a variety of reasons: Mistakes on the part of those providing instructions on how to use the method. Mistakes on the part of the method's users. Conscious user non-compliance with the method. Insurance providers sometimes impede access to medications (e.g. require prescription refills monthly) For instance, someone using oral forms of hormonal birth control might be given incorrect information by a health care provider as to the frequency of intake, or for some reason does not take the pill one or several days, or not go to the pharmacy on time to renew the prescription, or the pharmacy might be unwilling to provide enough pills to cover an extended absence. Effectiveness The table below color codes the typical use and perfect use failure rates, where the failure rate is measured as the expected number of pregnancies per year per woman using the method: {| class="wikitable sortable" |- style="background:#e0ffff" | style="text-align:right;"| Blue || style="text-align:right;"| under 1% || lower risk |- style="background:#e0ffe0" | style="text-align:right;"| Green || style="text-align:right;"| up to 5% || |- style="background:#ffffc0" | style="text-align:right;"| Yellow || style="text-align:right;"| up to 10% || |- style="background:#fda;" | style="text-align:right;"| Orange || style="text-align:right;"| up to 20% || |- style="background:#fcc;" | style="text-align:right;"| Red || style="text-align:right;"| over 20% || higher risk |- style="background:#dcdcdc" | style="text-align:right;"| Grey || style="text-align:right;"| no data || no data available |} For example, a failure rate of 20% means that 20 of 100 women become pregnant during the first year of use. Note that the rate may go above 100% if all women, on average, become pregnant within less than a year. In the degenerated case of all women becoming pregnant instantly, the rate would be infinite. In the user action required column, items that are non-user dependent (require action once per year or less) also have a blue background. Some methods may be used simultaneously for higher effectiveness rates. For example, using condoms with spermicides the estimated perfect use failure rate would be comparable to the perfect use failure rate of the implant. However, mathematically combining the rates to estimate the effectiveness of combined methods can be inaccurate, as the effectiveness of each method is not necessarily independent, except in the perfect case. If a method is known or suspected to have been ineffective, such as a condom breaking, or a method could not be used, as