Maybe you can use:  'year': fields.selection([(y, str(y)) for y in range(1970, (datetime.now().year + 30)+1 )], 'Year'),

Range from 1970 to 2044 (Adjust your range as you want)

and in the .xml file just add your field somewhere in your view:  <field name="year" />

easiest way is to add : 
'year':fields.char('Year', size="4")

aternative can be fields.integer('"Year")

both would need with some validity check on write 
adding field of type date will add full date format, and on view it will be shown as calendat widget...

in your python file it seems this :

class model_name(osv.osv)

      _name = "model.name"

     _description = "description for model"

    _columns = {

                  'year':fields.char('Year', size="4"),

}

model_name()

in your xml form view description it seems this :

    <!-- form -->   
     
    <record model="ir.ui.view" id="id_model_form">
            <field name="name">model.name.form</field>
            <field name="model">model.name</field>
            <field name="type">form</field>
            <field name="arch" type="xml">
                <form string="descripti" version="7.0" > 
                            <group>
                                <field name="year" />
                            </group>
                            
                </form>
            </field>
    </record>