We have three stock-based compensation plans. The 2006 Stock Incentive Plan was adopted in 2006 (“2006 Plan”) and had options granted under it through April 12, 2016. The 2016 Stock Incentive Plan (“2016 Plan”) was adopted in 2016 (“2016 Plan”) and had options granted under it through November 15, 2021. On October 11, 2021, the Board of Directors approved the 2021 Stock Incentive Plan (‘2021 Plan”) and on December 2, 2021, our shareholders approved the plan.

The Company recognizes compensation costs for those shares expected to vest on a straight-line basis over the requisite service period of the awards. The fair values of option awards granted in 2021 and 2020 were estimated using the Black-Sholes option pricing model under the following assumptions:

Given the limited public market for the Company’s stock, the Company has elected to estimate its expected volatility by benchmarking its volatility of several public company issuers that operate within its market segment. The guideline companies’ volatility was increased by a size adjustment premium to compensate for the difference in size between the guideline companies and the Company in its calculation. The first issuance for which this benchmarking was applied was effective with options granted on March 31, 2021.

2021 Stock Incentive Plan

The 2021 Plan became effective October 11, 2021 and expires October 11, 2031. The 2021 Plan provides for the granting of equity awards to key employees, including officers and directors. The maximum number of shares for which equity awards may be granted under the 2021 Plan is 5,000,000. Options under the 2021 Plan expire no later than ten years from the date of grant or after prescribed periods of time after employment ceases, whichever comes first, and vest over periods determined by the Board of Directors. The minimum exercise price of each option is the fair market value of the Company’s stock on the date of grant. Under the Plan, fair market value means the average of the reported high and low sale prices of our common stock on the Nasdaq Stock Market. As of December 31, 2021 there were 1,590,000 outstanding unexpired options issued under the 2021 Plan, of which 1,000,000 were exercisable, and there were 3,410,000 options available to be granted.

2016 Stock Incentive Plan

The 2016 Plan became effective June 1, 2016 and expires April 4, 2026. The 2016 Plan provides for the granting of equity awards to key employees, including officers and directors. The maximum number of shares for which equity awards may be granted under the 2016 Plan is 1,000,000. Options under the 2016 Plan expire no later than ten years from the date of grant or after prescribed periods of time after employment ceases, whichever comes first, and vest over periods determined by the Board of Directors. The minimum exercise price of each option is the quoted market price of the Company’s stock on the date of grant. As of December 31, 2021 and 2020, there were 940,500 and 606,000 options, respectively, of outstanding unexpired options under the 2016 Plan, of which 578,000 and 371,000 were exercisable, respectively. No additional options may be granted under the 2016 Plan.

2006 Stock Incentive Plan

The 2006 Plan became effective May 18, 2006, and expired April 12, 2016. The 2006 Plan provides for the granting of equity awards to key employees, including officers and directors. The maximum number of shares for which equity awards could be granted under the 2006 Plan was 1,950,000. Options under the 2006 Plan expire no later than ten years from the date of grant or after prescribed periods of time after employment ceases, whichever comes first, and vested over periods determined by the Board of Directors. There were 374,000 and 789,000 outstanding unexpired options remaining from the 2006 Plan as of December 31, 2021 and 2020, respectively, all of which were exercisable.

The status of the options issued under the foregoing option plans as of December 31, 2021 and 2020, and changes during the years ended December 31, 2021 and 2020, were as follows:

Nonvested stock option awards as of December 31, 2021 and 2020, and changes during the years ended December 31, 2021 and 2020, were as follows:

As of December 31, 2021, unrecognized compensation cost associated with non-vested share-based employee and non-employee compensation totaled $1,200,704, which is expected to be recognized over a weighted average period of ten months.